Complications related to the use of silicone subclavian catheters for hemodialysis were prospectively studied in 21 consecutive patients with acute and chronic renal failure. Between July 1991 and December 1992, 34 double-lumen silicone catheters (Medcomp; 12 French; 20 or 24 cm) were inserted in 21 patients. The mean duration of catheterization was 20 days (range, 2-58 days). Venograms were performed in 16 patients (22 subclavian veins) within 6 months following removal of the catheter. Excluded from angiography were patients whose catheters had been in place less than 1 week or who underwent fewer than 3 dialysis sessions because of minor risk of stenosis. Patients who had ipsilateral repeated catheters were also excluded. Two angiographies showed subclavian vein stenosis, both occurring in the same patient. One showed 50% stenosis with collaterals; one showed 50% stenosis without collaterals. One other complication was a pneumothorax. Catheter thrombosis was observed in 3 patients; catheter sepsis did not occur. We conclude that use of silicone catheters for subclavian cannulation is safe and effective to provide temporary vascular access for acute hemodialysis. The incidence of subclavian vein stenosis is lower compared with polytetrafluoroethylene and polyurethane catheters.