diff --git a/frontend/src/hooks/__tests__/useCases.test.ts b/frontend/src/hooks/__tests__/useCases.test.ts
new file mode 100644
index 0000000..4b7694c
--- /dev/null
+++ b/frontend/src/hooks/__tests__/useCases.test.ts
@@ -0,0 +1,291 @@
+import { describe, it, expect } from 'vitest'
+import { waitFor, act } from '@testing-library/react'
+import { http, HttpResponse } from 'msw'
+import { server } from '@/test/mocks/server'
+import { renderHookWithProviders } from '@/test/utils'
+import {
+  mockCase,
+  mockCaseListResponse,
+  mockEmptyCaseList,
+} from '@/test/mocks/data'
+import {
+  useCases,
+  usePendingIcdCases,
+  useCaseUpdate,
+  useKvnrUpdate,
+  useIcdUpdate,
+} from '@/hooks/useCases'
+import type { CaseFilters } from '@/hooks/useCases'
+
+// ---------------------------------------------------------------------------
+// useCases
+// ---------------------------------------------------------------------------
+
+describe('useCases', () => {
+  const defaultFilters: CaseFilters = { page: 1, per_page: 20 }
+
+  it('fetches cases with default filters (success)', async () => {
+    const { result } = renderHookWithProviders(() => useCases(defaultFilters))
+
+    await waitFor(() => expect(result.current.isSuccess).toBe(true))
+
+    expect(result.current.data).toEqual(mockCaseListResponse)
+    expect(result.current.data!.items).toHaveLength(2)
+    expect(result.current.data!.total).toBe(2)
+  })
+
+  it('passes filter params to the API (search, jahr, fallgruppe, has_icd)', async () => {
+    const capturedParams: Record<string, string | null> = {}
+
+    server.use(
+      http.get('/api/cases/', ({ request }) => {
+        const url = new URL(request.url)
+        capturedParams.search = url.searchParams.get('search')
+        capturedParams.jahr = url.searchParams.get('jahr')
+        capturedParams.fallgruppe = url.searchParams.get('fallgruppe')
+        capturedParams.has_icd = url.searchParams.get('has_icd')
+        capturedParams.page = url.searchParams.get('page')
+        capturedParams.per_page = url.searchParams.get('per_page')
+        return HttpResponse.json(mockCaseListResponse)
+      }),
+    )
+
+    const filters: CaseFilters = {
+      page: 2,
+      per_page: 10,
+      search: 'Meier',
+      jahr: 2026,
+      fallgruppe: 'onko',
+      has_icd: 'true',
+    }
+
+    const { result } = renderHookWithProviders(() => useCases(filters))
+
+    await waitFor(() => expect(result.current.isSuccess).toBe(true))
+
+    expect(capturedParams.search).toBe('Meier')
+    expect(capturedParams.jahr).toBe('2026')
+    expect(capturedParams.fallgruppe).toBe('onko')
+    expect(capturedParams.has_icd).toBe('true')
+    expect(capturedParams.page).toBe('2')
+    expect(capturedParams.per_page).toBe('10')
+  })
+
+  it('does not send optional params when they are undefined', async () => {
+    const capturedParams: Record<string, string | null> = {}
+
+    server.use(
+      http.get('/api/cases/', ({ request }) => {
+        const url = new URL(request.url)
+        capturedParams.search = url.searchParams.get('search')
+        capturedParams.jahr = url.searchParams.get('jahr')
+        capturedParams.fallgruppe = url.searchParams.get('fallgruppe')
+        capturedParams.has_icd = url.searchParams.get('has_icd')
+        return HttpResponse.json(mockCaseListResponse)
+      }),
+    )
+
+    const { result } = renderHookWithProviders(() => useCases(defaultFilters))
+
+    await waitFor(() => expect(result.current.isSuccess).toBe(true))
+
+    expect(capturedParams.search).toBeNull()
+    expect(capturedParams.jahr).toBeNull()
+    expect(capturedParams.fallgruppe).toBeNull()
+    expect(capturedParams.has_icd).toBeNull()
+  })
+
+  it('respects enabled: false (fetchStatus === "idle")', () => {
+    const { result } = renderHookWithProviders(() =>
+      useCases(defaultFilters, { enabled: false }),
+    )
+
+    expect(result.current.fetchStatus).toBe('idle')
+    expect(result.current.data).toBeUndefined()
+  })
+
+  it('handles empty response', async () => {
+    server.use(
+      http.get('/api/cases/', () => {
+        return HttpResponse.json(mockEmptyCaseList)
+      }),
+    )
+
+    const { result } = renderHookWithProviders(() => useCases(defaultFilters))
+
+    await waitFor(() => expect(result.current.isSuccess).toBe(true))
+
+    expect(result.current.data!.items).toHaveLength(0)
+    expect(result.current.data!.total).toBe(0)
+  })
+
+  it('handles server error (500)', async () => {
+    server.use(
+      http.get('/api/cases/', () => {
+        return new HttpResponse(null, { status: 500 })
+      }),
+    )
+
+    const { result } = renderHookWithProviders(() => useCases(defaultFilters))
+
+    await waitFor(() => expect(result.current.isError).toBe(true))
+
+    expect(result.current.data).toBeUndefined()
+  })
+})
+
+// ---------------------------------------------------------------------------
+// usePendingIcdCases
+// ---------------------------------------------------------------------------
+
+describe('usePendingIcdCases', () => {
+  it('fetches pending ICD cases (success)', async () => {
+    const { result } = renderHookWithProviders(() => usePendingIcdCases(1, 20))
+
+    await waitFor(() => expect(result.current.isSuccess).toBe(true))
+
+    expect(result.current.data!.items).toHaveLength(1)
+    expect(result.current.data!.items[0].icd).toBeNull()
+    expect(result.current.data!.total).toBe(1)
+  })
+
+  it('respects enabled: false', () => {
+    const { result } = renderHookWithProviders(() =>
+      usePendingIcdCases(1, 20, { enabled: false }),
+    )
+
+    expect(result.current.fetchStatus).toBe('idle')
+    expect(result.current.data).toBeUndefined()
+  })
+})
+
+// ---------------------------------------------------------------------------
+// useCaseUpdate
+// ---------------------------------------------------------------------------
+
+describe('useCaseUpdate', () => {
+  it('updates a case and returns the result', async () => {
+    const { result } = renderHookWithProviders(() => useCaseUpdate())
+
+    let updated: unknown
+    await act(async () => {
+      updated = await result.current.mutateAsync({
+        id: 1,
+        data: { kommentar: 'Neuer Kommentar' },
+      })
+    })
+
+    expect((updated as { id: number }).id).toBe(1)
+    await waitFor(() => expect(result.current.isSuccess).toBe(true))
+  })
+
+  it('handles error (403 Forbidden)', async () => {
+    server.use(
+      http.put('/api/cases/:id', () => {
+        return HttpResponse.json(
+          { detail: 'Forbidden' },
+          { status: 403 },
+        )
+      }),
+    )
+
+    const { result } = renderHookWithProviders(() => useCaseUpdate())
+
+    await act(async () => {
+      try {
+        await result.current.mutateAsync({ id: 1, data: { kommentar: 'x' } })
+      } catch {
+        // expected
+      }
+    })
+
+    await waitFor(() => expect(result.current.isError).toBe(true))
+  })
+})
+
+// ---------------------------------------------------------------------------
+// useKvnrUpdate
+// ---------------------------------------------------------------------------
+
+describe('useKvnrUpdate', () => {
+  it('updates KVNR and returns the updated case', async () => {
+    const { result } = renderHookWithProviders(() => useKvnrUpdate())
+
+    let updated: unknown
+    await act(async () => {
+      updated = await result.current.mutateAsync({
+        id: 1,
+        kvnr: 'C111222333',
+      })
+    })
+
+    expect((updated as { kvnr: string }).kvnr).toBe('C111222333')
+    await waitFor(() => expect(result.current.isSuccess).toBe(true))
+  })
+
+  it('handles null KVNR', async () => {
+    server.use(
+      http.put('/api/cases/:id/kvnr', ({ params }) => {
+        const id = Number(params.id)
+        return HttpResponse.json({ ...mockCase, id, kvnr: null })
+      }),
+    )
+
+    const { result } = renderHookWithProviders(() => useKvnrUpdate())
+
+    let updated: unknown
+    await act(async () => {
+      updated = await result.current.mutateAsync({
+        id: 1,
+        kvnr: null,
+      })
+    })
+
+    expect((updated as { kvnr: string | null }).kvnr).toBeNull()
+    await waitFor(() => expect(result.current.isSuccess).toBe(true))
+  })
+})
+
+// ---------------------------------------------------------------------------
+// useIcdUpdate
+// ---------------------------------------------------------------------------
+
+describe('useIcdUpdate', () => {
+  it('updates ICD and returns the updated case', async () => {
+    const { result } = renderHookWithProviders(() => useIcdUpdate())
+
+    let updated: unknown
+    await act(async () => {
+      updated = await result.current.mutateAsync({
+        id: 1,
+        icd: 'C61',
+      })
+    })
+
+    expect((updated as { icd: string }).icd).toBe('C61')
+    await waitFor(() => expect(result.current.isSuccess).toBe(true))
+  })
+
+  it('handles error (422 Unprocessable Entity)', async () => {
+    server.use(
+      http.put('/api/cases/:id/icd', () => {
+        return HttpResponse.json(
+          { detail: 'Invalid ICD code' },
+          { status: 422 },
+        )
+      }),
+    )
+
+    const { result } = renderHookWithProviders(() => useIcdUpdate())
+
+    await act(async () => {
+      try {
+        await result.current.mutateAsync({ id: 1, icd: 'INVALID' })
+      } catch {
+        // expected
+      }
+    })
+
+    await waitFor(() => expect(result.current.isError).toBe(true))
+  })
+})
diff --git a/frontend/src/hooks/__tests__/useDashboard.test.ts b/frontend/src/hooks/__tests__/useDashboard.test.ts
new file mode 100644
index 0000000..388818b
--- /dev/null
+++ b/frontend/src/hooks/__tests__/useDashboard.test.ts
@@ -0,0 +1,51 @@
+import { describe, it, expect } from 'vitest'
+import { waitFor } from '@testing-library/react'
+import { http, HttpResponse } from 'msw'
+import { server } from '@/test/mocks/server'
+import { renderHookWithProviders } from '@/test/utils'
+import { mockDashboardResponse } from '@/test/mocks/data'
+import { useDashboard } from '@/hooks/useDashboard'
+
+describe('useDashboard', () => {
+  it('fetches dashboard data for the given year', async () => {
+    const { result } = renderHookWithProviders(() => useDashboard(2026))
+
+    await waitFor(() => expect(result.current.isSuccess).toBe(true))
+
+    expect(result.current.data).toEqual(mockDashboardResponse)
+    expect(result.current.data!.kpis.total_cases).toBe(142)
+    expect(result.current.data!.weekly).toHaveLength(6)
+  })
+
+  it('includes the year parameter in the API call', async () => {
+    let capturedJahr: string | null = null
+
+    server.use(
+      http.get('/api/reports/dashboard', ({ request }) => {
+        const url = new URL(request.url)
+        capturedJahr = url.searchParams.get('jahr')
+        return HttpResponse.json(mockDashboardResponse)
+      }),
+    )
+
+    const { result } = renderHookWithProviders(() => useDashboard(2025))
+
+    await waitFor(() => expect(result.current.isSuccess).toBe(true))
+
+    expect(capturedJahr).toBe('2025')
+  })
+
+  it('handles server error (500)', async () => {
+    server.use(
+      http.get('/api/reports/dashboard', () => {
+        return new HttpResponse(null, { status: 500 })
+      }),
+    )
+
+    const { result } = renderHookWithProviders(() => useDashboard(2026))
+
+    await waitFor(() => expect(result.current.isError).toBe(true))
+
+    expect(result.current.data).toBeUndefined()
+  })
+})