A modification of a classic Johnson stone basket has been made, such that this basket can pass easily over an angiographic guide wire. With this modification, the Johnson stone basket is an excellent instrument for use in an antegrade or a retrograde fashion for retrieving impacted ureteral calculi. Eleven patients had ureteral calculi manipulated. Of the six ureteral calculi manipulated with standard retractable baskets, only three were successfully extracted from impacted positions. Of the five manipulated with the modified Johnson stone basket, however, four were successfully extracted. The modified Johnson stone basket is an essential instrument in percutaneous manipulation of ureteral calculi.