Forty-three evaluable patients with hematologic malignancies, mainly acute leukemia, were prospectively randomized to receive a double lumen central venous catheter or a totally implantable venous access system. The mean catheter stay was 166 days (median, 104 days) for the 23 double lumen catheters and 164 days (median, 65 days) for implanted systems. Exit site infections were not encountered in double lumen catheters, but there were two proven infections around the injection port of implanted devices. Tunnel infections did not occur. Seven double lumen catheters and four implanted systems were removed because of infection. Staphylococcus epidermidis was the predominant microorganism cultured from these catheters. Five of nine patients with double lumen catheters and catheter-related S. epidermidis infection and the two patients with implanted systems in whom S. epidermidis was cultured were on selective gut decontamination. The pattern of infection did not seem to be influenced by this regimen. Totally implantable systems proved to be as safe as double lumen central venous lines.