diff --git a/cmd_sorted_set.go b/cmd_sorted_set.go
index e92c82a..bc1afc0 100644
--- a/cmd_sorted_set.go
+++ b/cmd_sorted_set.go
@@ -825,6 +825,12 @@ func (m *Miniredis) makeCmdZrank(reverse bool) server.Cmd {
 		withTx(m, c, func(c *server.Peer, ctx *connCtx) {
 			db := m.db(ctx.selectedDB)
 
+			withScore := false
+			if len(args) > 0 && strings.ToUpper(args[len(args)-1]) == "WITHSCORE" {
+				withScore = true
+				args = args[:len(args)-1]
+			}
+
 			if len(args) > 2 {
 				setDirty(c)
 				c.WriteError(msgSyntaxError)
@@ -832,7 +838,11 @@ func (m *Miniredis) makeCmdZrank(reverse bool) server.Cmd {
 			}
 
 			if !db.exists(key) {
-				c.WriteNull()
+				if withScore {
+					c.WriteLen(-1)
+				} else {
+					c.WriteNull()
+				}
 				return
 			}
 
@@ -847,10 +857,21 @@ func (m *Miniredis) makeCmdZrank(reverse bool) server.Cmd {
 			}
 			rank, ok := db.ssetRank(key, member, direction)
 			if !ok {
-				c.WriteNull()
+				if withScore {
+					c.WriteLen(-1)
+				} else {
+					c.WriteNull()
+				}
 				return
 			}
-			c.WriteInt(rank)
+
+			if withScore {
+				c.WriteLen(2)
+				c.WriteInt(rank)
+				c.WriteFloat(db.ssetScore(key, member))
+			} else {
+				c.WriteInt(rank)
+			}
 		})
 	}
 }
diff --git a/cmd_sorted_set_test.go b/cmd_sorted_set_test.go
index 670110e..a4040d6 100644
--- a/cmd_sorted_set_test.go
+++ b/cmd_sorted_set_test.go
@@ -30,10 +30,27 @@ func TestSortedSet(t *testing.T) {
 			proto.Int(2),
 		)
 
+		mustDo(t, c,
+			"ZRANK", "z", "three", "withscore",
+			proto.Array(
+				proto.Int(2),
+				proto.String("3"),
+			),
+		)
+
 		mustDo(t, c,
 			"ZREVRANK", "z", "one",
 			proto.Int(2),
 		)
+
+		mustDo(t, c,
+			"ZREVRANK", "z", "one", "withscore",
+			proto.Array(
+				proto.Int(2),
+				proto.String("1"),
+			),
+		)
+
 		must0(t, c,
 			"ZREVRANK", "z", "three",
 		)
diff --git a/integration/sorted_set_test.go b/integration/sorted_set_test.go
index 79ff45b..72b9abf 100644
--- a/integration/sorted_set_test.go
+++ b/integration/sorted_set_test.go
@@ -18,13 +18,18 @@ func TestSortedSet(t *testing.T) {
 		c.Do("ZRANK", "z", "mies")
 		c.Do("ZRANK", "z", "vuur")
 		c.Do("ZRANK", "z", "nosuch")
+		c.Do("ZRANK", "z", "vuur", "WITHSCORE")
 		c.Do("ZRANK", "nosuch", "nosuch")
+		c.Do("ZRANK", "z", "nosuch", "WITHSCORE")
+		c.Do("ZRANK", "nosuch", "nosuch", "WITHSCORE")
 		c.Do("ZREVRANK", "z", "aap")
 		c.Do("ZREVRANK", "z", "noot")
 		c.Do("ZREVRANK", "z", "mies")
 		c.Do("ZREVRANK", "z", "vuur")
 		c.Do("ZREVRANK", "z", "nosuch")
 		c.Do("ZREVRANK", "nosuch", "nosuch")
+		c.Do("ZREVRANK", "z", "noot", "WITHSCORE")
+		c.Do("ZREVRANK", "nosuch", "nosuch", "WITHSCORE")
 
 		c.Do("ZADD", "zi", "inf", "aap", "-inf", "noot", "+inf", "mies")
 		c.Do("ZRANK", "zi", "noot")
@@ -70,6 +75,8 @@ func TestSortedSet(t *testing.T) {
 		c.Error("wrong number", "ZPOPMIN")
 		c.Error("out of range", "ZPOPMIN", "set", "noint")
 		c.Error("syntax error", "ZPOPMIN", "set", "1", "toomany")
+		c.Error("syntax error", "ZRANK", "z", "nosuch", "WITHSCORES")
+		c.Error("syntax error", "ZREVRANK", "z", "nosuch", "WITHSCORES")
 
 		c.Do("RENAME", "z", "z2")
 		c.Do("EXISTS", "z")