diff --git a/pkg/github/client.go b/pkg/github/client.go
index 3647b98..40cc3f7 100644
--- a/pkg/github/client.go
+++ b/pkg/github/client.go
@@ -28,12 +28,23 @@ func (f *IssueFetcher) FetchIssues(ctx context.Context, owner, repo string, sinc
 	}
 
 	var allIssues []*github.Issue
+	seen := make(map[string]struct{})
 	for {
 		issues, resp, err := f.client.Issues.ListByRepository(ctx, owner, repo, opt)
 		if err != nil {
 			return nil, fmt.Errorf("failed to list issues: %w", err)
 		}
-		allIssues = append(allIssues, issues...)
+		for _, issue := range issues {
+			key := issue.GetURL()
+			if key == "" {
+				key = fmt.Sprintf("id:%d", issue.GetID())
+			}
+			if _, ok := seen[key]; ok {
+				continue
+			}
+			seen[key] = struct{}{}
+			allIssues = append(allIssues, issue)
+		}
 		if resp.NextPage == 0 {
 			break
 		}
diff --git a/pkg/github/client_test.go b/pkg/github/client_test.go
index 884b946..4c31251 100644
--- a/pkg/github/client_test.go
+++ b/pkg/github/client_test.go
@@ -21,7 +21,8 @@ func TestFetchIssues_Pagination(t *testing.T) {
 	sinceTime := time.Now().Add(-24 * time.Hour).Truncate(time.Second)
 	sinceStr := sinceTime.Format(time.RFC3339)
 
-	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	var server *httptest.Server
+	server = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		q := r.URL.Query()
 		if q.Get("since") != sinceStr {
 			t.Errorf("expected since parameter %q, got %q", sinceStr, q.Get("since"))
@@ -96,7 +97,8 @@ func TestFetchIssues_Pagination(t *testing.T) {
 }
 
 func TestFetchIssues_RateLimit(t *testing.T) {
-	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	var server *httptest.Server
+	server = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("X-RateLimit-Limit", "60")
 		w.Header().Set("X-RateLimit-Remaining", "0")
 		w.Header().Set("X-RateLimit-Reset", strconv.FormatInt(time.Now().Add(1*time.Hour).Unix(), 10))
@@ -122,7 +124,8 @@ func TestFetchIssues_RateLimit(t *testing.T) {
 }
 
 func TestFetchIssues_EmptyPageWithNext(t *testing.T) {
-	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	var server *httptest.Server
+	server = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		q := r.URL.Query()
 		pageStr := q.Get("page")
 		page := 1
@@ -176,6 +179,76 @@ func TestFetchIssues_EmptyPageWithNext(t *testing.T) {
 	}
 }
 
+func TestFetchIssues_DeduplicatesAcrossPages(t *testing.T) {
+	sinceTime := time.Now().Add(-24 * time.Hour).Truncate(time.Second)
+	sinceStr := sinceTime.Format(time.RFC3339)
+	requests := 0
+
+	var server *httptest.Server
+	server = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		requests++
+		if got := r.URL.Query().Get("since"); got != sinceStr {
+			t.Fatalf("expected since parameter %q, got %q", sinceStr, got)
+		}
+
+		page := 1
+		if rawPage := r.URL.Query().Get("page"); rawPage != "" {
+			parsedPage, err := strconv.Atoi(rawPage)
+			if err != nil {
+				t.Fatalf("invalid page parameter: %v", err)
+			}
+			page = parsedPage
+		}
+
+		duplicateURL := "https://api.github.com/repos/owner/repo/issues/42"
+		var issues []*github.Issue
+		switch page {
+		case 1:
+			issues = []*github.Issue{
+				{ID: github.Int64(42), URL: github.String(duplicateURL), Title: github.String("duplicate")},
+				{ID: github.Int64(43), URL: github.String("https://api.github.com/repos/owner/repo/issues/43")},
+			}
+			w.Header().Set("Link", fmt.Sprintf("<%s?page=2&since=%s>; rel=\"next\"", server.URL+r.URL.Path, url.QueryEscape(sinceStr)))
+		case 2:
+			issues = []*github.Issue{
+				{ID: github.Int64(42), URL: github.String(duplicateURL), Title: github.String("duplicate again")},
+				{ID: github.Int64(44), URL: github.String("https://api.github.com/repos/owner/repo/issues/44")},
+			}
+		default:
+			t.Fatalf("unexpected page request: %d", page)
+		}
+
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(issues)
+	}))
+	defer server.Close()
+
+	client := github.NewClient(server.Client())
+	baseURL, _ := url.Parse(server.URL + "/")
+	client.BaseURL = baseURL
+
+	fetcher := NewIssueFetcher(client)
+	issues, err := fetcher.FetchIssues(context.Background(), "owner", "repo", sinceTime, 2)
+	if err != nil {
+		t.Fatalf("FetchIssues failed: %v", err)
+	}
+
+	if requests != 2 {
+		t.Fatalf("expected 2 paginated requests, got %d", requests)
+	}
+	if len(issues) != 3 {
+		t.Fatalf("expected 3 unique issues, got %d", len(issues))
+	}
+
+	gotIDs := []int64{issues[0].GetID(), issues[1].GetID(), issues[2].GetID()}
+	wantIDs := []int64{42, 43, 44}
+	for i := range wantIDs {
+		if gotIDs[i] != wantIDs[i] {
+			t.Fatalf("at index %d: expected ID %d, got %d", i, wantIDs[i], gotIDs[i])
+		}
+	}
+}
+
 func TestFetchIssues_Integration(t *testing.T) {
 	token := os.Getenv("GITHUB_TOKEN")
 	repoFullName := os.Getenv("GITHUB_REPOSITORY")