diff --git a/cluster_commands.go b/cluster_commands.go
new file mode 100644
index 0000000..dff62c9
--- /dev/null
+++ b/cluster_commands.go
@@ -0,0 +1,22 @@
+package redis
+
+import "sync/atomic"
+
+func (c *ClusterClient) DBSize() *IntCmd {
+	cmd := NewIntCmd("dbsize")
+	var size int64
+	err := c.ForEachMaster(func(master *Client) error {
+		n, err := master.DBSize().Result()
+		if err != nil {
+			return err
+		}
+		atomic.AddInt64(&size, n)
+		return nil
+	})
+	if err != nil {
+		cmd.setErr(err)
+		return cmd
+	}
+	cmd.val = size
+	return cmd
+}
diff --git a/cluster_test.go b/cluster_test.go
index b2106da..6f3677b 100644
--- a/cluster_test.go
+++ b/cluster_test.go
@@ -475,11 +475,9 @@ var _ = Describe("ClusterClient", func() {
 			})
 			Expect(err).NotTo(HaveOccurred())
 
-			for _, client := range cluster.masters() {
-				size, err := client.DBSize().Result()
-				Expect(err).NotTo(HaveOccurred())
-				Expect(size).To(Equal(int64(0)))
-			}
+			size, err := client.DBSize().Result()
+			Expect(err).NotTo(HaveOccurred())
+			Expect(size).To(Equal(int64(0)))
 		})
 
 		It("should CLUSTER SLOTS", func() {