In a 5-year period (January 1987 to December 1991) a total of 285 US-guided nephrostomy procedures were performed in 159 patients. All nephrostomies were performed with a 2.3 mm one-step trochar catheter without internal fixation. The hospital case records were reviewed retrospectively, and complications were registered. The overall success rate was 92%. The catheters were maintained for a median of 17 days (range 1-150 days). Thirty-three catheters slipped out unintentionally in the first 10 days. Haematuria through the catheter for more than 3 days occurred in 14 cases. Complications occurred in 19 (6.7%) of the procedures. One uraemic patient had cardiac arrest but was resuscitated. Two patients had severe haematuria and one of them had a nephrectomy. Seven patients developed septicaemia, and 6 had perirenal bleeding or urinary leakage. Three patients developed skin infection. Ultrasound-guided nephrostomy is a gentle procedure with only few major complications, but the risk of the procedure should still be weighed against the expected benefit.