diff --git a/handler.go b/handler.go
index 491e019..02ab3fe 100644
--- a/handler.go
+++ b/handler.go
@@ -58,7 +58,7 @@ var tmpl = template.Must(template.New("").Funcs(template.FuncMap{
 var validToken = regexp.MustCompile(`^[a-f0-9]{32}$`)
 
 func registerRoutes(mux *http.ServeMux, store *Store) {
-	mux.HandleFunc("GET /health", handleHealth)
+	mux.HandleFunc("GET /health", handleHealth(store))
 	mux.HandleFunc("GET /", handleIndex)
 	mux.HandleFunc("POST /lists", handleCreateList(store))
 	mux.HandleFunc("GET /lists/{token}", handleShowList(store))
@@ -70,15 +70,20 @@ func registerRoutes(mux *http.ServeMux, store *Store) {
 	mux.HandleFunc("POST /lists/{token}/delete", handleDeleteList(store))
 }
 
-func handleHealth(w http.ResponseWriter, r *http.Request) {
-	w.Header().Set("Content-Type", "application/json")
-	w.WriteHeader(http.StatusOK)
-	json.NewEncoder(w).Encode(map[string]string{ //nolint:errcheck
-		"status":    "ok",
-		"service":   "bringit",
-		"uptime":    time.Since(startTime).Round(time.Second).String(),
-		"timestamp": time.Now().UTC().Format(time.RFC3339),
-	})
+func handleHealth(store *Store) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		listCount, itemCount := store.Stats()
+		w.Header().Set("Content-Type", "application/json")
+		w.WriteHeader(http.StatusOK)
+		json.NewEncoder(w).Encode(map[string]any{ //nolint:errcheck
+			"status":     "ok",
+			"service":    "bringit",
+			"uptime":     time.Since(startTime).Round(time.Second).String(),
+			"timestamp":  time.Now().UTC().Format(time.RFC3339),
+			"list_count": listCount,
+			"item_count": itemCount,
+		})
+	}
 }
 
 func handleIndex(w http.ResponseWriter, r *http.Request) {
diff --git a/handler_test.go b/handler_test.go
index 4054cee..d68e199 100644
--- a/handler_test.go
+++ b/handler_test.go
@@ -29,19 +29,46 @@ func TestHealthEndpoint(t *testing.T) {
 	if ct := w.Header().Get("Content-Type"); !strings.HasPrefix(ct, "application/json") {
 		t.Fatalf("expected application/json content-type, got %s", ct)
 	}
-	var body map[string]string
+	var body map[string]any
 	if err := json.NewDecoder(w.Body).Decode(&body); err != nil {
 		t.Fatalf("failed to decode JSON: %v", err)
 	}
 	if body["status"] != "ok" {
-		t.Fatalf("expected status=ok, got %s", body["status"])
+		t.Fatalf("expected status=ok, got %v", body["status"])
 	}
 	if body["service"] != "bringit" {
-		t.Fatalf("expected service=bringit, got %s", body["service"])
+		t.Fatalf("expected service=bringit, got %v", body["service"])
 	}
-	if body["timestamp"] == "" {
+	if body["timestamp"] == nil || body["timestamp"] == "" {
 		t.Fatal("expected non-empty timestamp")
 	}
+	if body["list_count"] != float64(0) {
+		t.Fatalf("expected list_count=0, got %v", body["list_count"])
+	}
+	if body["item_count"] != float64(0) {
+		t.Fatalf("expected item_count=0, got %v", body["item_count"])
+	}
+}
+
+func TestHealthEndpointWithData(t *testing.T) {
+	mux, store := setupTestServer()
+	l := store.CreateList("テスト", "")
+	store.AddItem(l.ShareToken, "テント", "太郎", true)
+	store.AddItem(l.ShareToken, "寝袋", "花子", false)
+
+	req := httptest.NewRequest("GET", "/health", nil)
+	w := httptest.NewRecorder()
+	mux.ServeHTTP(w, req)
+
+	var body map[string]any
+	json.NewDecoder(w.Body).Decode(&body)
+
+	if body["list_count"] != float64(1) {
+		t.Fatalf("expected list_count=1, got %v", body["list_count"])
+	}
+	if body["item_count"] != float64(2) {
+		t.Fatalf("expected item_count=2, got %v", body["item_count"])
+	}
 }
 
 func TestIndexPage(t *testing.T) {
diff --git a/store.go b/store.go
index 8ce2921..981d50f 100644
--- a/store.go
+++ b/store.go
@@ -124,6 +124,16 @@ func (s *Store) DeleteList(token string) bool {
 	return true
 }
 
+func (s *Store) Stats() (listCount int, itemCount int) {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	listCount = len(s.lists)
+	for _, l := range s.lists {
+		itemCount += len(l.Items)
+	}
+	return
+}
+
 func (s *Store) DeleteItem(token, itemID string) {
 	s.mu.Lock()
 	defer s.mu.Unlock()
diff --git a/store_test.go b/store_test.go
index bd7b1ff..71c89e6 100644
--- a/store_test.go
+++ b/store_test.go
@@ -156,6 +156,39 @@ func TestConcurrentAddItem(t *testing.T) {
 	}
 }
 
+func TestStoreStats(t *testing.T) {
+	s := NewStore()
+
+	listCount, itemCount := s.Stats()
+	if listCount != 0 || itemCount != 0 {
+		t.Fatalf("expected 0/0, got %d/%d", listCount, itemCount)
+	}
+
+	l1 := s.CreateList("リスト1", "")
+	s.AddItem(l1.ShareToken, "アイテム1", "", true)
+	s.AddItem(l1.ShareToken, "アイテム2", "", false)
+
+	l2 := s.CreateList("リスト2", "")
+	s.AddItem(l2.ShareToken, "アイテム3", "", true)
+
+	listCount, itemCount = s.Stats()
+	if listCount != 2 {
+		t.Fatalf("expected 2 lists, got %d", listCount)
+	}
+	if itemCount != 3 {
+		t.Fatalf("expected 3 items, got %d", itemCount)
+	}
+
+	s.DeleteList(l1.ShareToken)
+	listCount, itemCount = s.Stats()
+	if listCount != 1 {
+		t.Fatalf("expected 1 list after deletion, got %d", listCount)
+	}
+	if itemCount != 1 {
+		t.Fatalf("expected 1 item after deletion, got %d", itemCount)
+	}
+}
+
 func TestGetEnv(t *testing.T) {
 	// 環境変数が設定されている場合
 	os.Setenv("TEST_VAR", "hello")