In this study we evaluated the catheter-related complications in 52 patients with advanced melanoma, renal cell cancer or non-Hodgkin's lymphoma treated with continuous infusion of low-dose recombinant interleukin-2 by central venous access (CVA) of the port-a-cath type. We noted a high incidence (55.5%) of catheter infection, defined as positive blood cultures drawn from the CVA in symptomatic or asymptomatic patients. Six infections were noted before rIL-2 treatment was started. Twelve of the 30 documented infections were symptomatic (fever and/or chills), with only four documented bacteraemias. The most frequently cultured microorganism was Staphylococcus epidermidis (73%). Treatment initially consisted of systemic antibiotics via the CVA, but as experience increased, the mostly asymptomatic CVA infections were not treated. In 30% of the documented CVA infections a thrombus at the tip of the catheter was found by radiological contrast examination. Local thrombosis can be effectively treated with constant infusion of low dose streptokinase via the CVA.