diff --git a/write.go b/write.go
index cfbd568..3f5fb57 100644
--- a/write.go
+++ b/write.go
@@ -34,6 +34,9 @@ func (e *Encoder) encodeStruct(val reflect.Value) error {
 func (e *Encoder) encodeMap(val reflect.Value) error {
 	for _, k := range val.MapKeys() {
 		v := val.MapIndex(k)
+		if v.Kind() == reflect.Map {
+			return encodeMap(v)
+		}
 
 		if err := e.writeTuple(k.Interface(), v); err != nil {
 			return err