diff --git a/values.go b/values.go
index 0c571d74..e7e6c1f7 100644
--- a/values.go
+++ b/values.go
@@ -189,7 +189,15 @@ func encodePreparedStatementArgument(ci *pgtype.ConnInfo, buf []byte, oid pgtype
 
 		sp := len(buf)
 		buf = pgio.AppendInt32(buf, -1)
-		argBuf, err := value.(pgtype.BinaryEncoder).EncodeBinary(ci, buf)
+		var argBuf []byte
+		switch valueEncoder := value.(type) {
+		case pgtype.BinaryEncoder:
+			argBuf, err = valueEncoder.EncodeBinary(ci, buf)
+		case pgtype.TextEncoder:
+			argBuf, err = valueEncoder.EncodeText(ci, buf)
+		default:
+			return nil, fmt.Errorf("invalid encode type %v", valueEncoder)
+		}
 		if err != nil {
 			return nil, err
 		}