In an open study, 42 venous Port-A-Cath systems (PAC) were implanted in 40 patients with AML (12), ALL/AUL (11), NHL with bone marrow infiltration (8), Hodgkin's lymphoma (3), solid tumors (5) and severe aplastic anemia (1). Mean duration of system use was 212 days. The cumulated duration of use of all systems was 8.883 days. 1,627 blood samples were taken from the PAC. Blood sampling was possible on 8,696 of 8,883 days of cumulated access (98%). A total of 522 blood transfusions were administrated. Fifty-two episodes of neutropenia (granulocyte counts less than 0.5 x 10(9)/l) with a mean duration of 17 days were observed in the group of the 23 patients with acute leukemias. A total of 25 complications were registered. The incidence was 2.8/1,000 days of access. Twelve complications were regarded as severe. Venous thrombosis was observed in 3 cases. In addition, there were 2 disruptions of the catheter, 1 disconnection, 1 looping and 4 local infections. The rate of systemic infection could not be accurately estimated because the catheter was always left in place and antibiotic treatment was started immediately in case of fever with or without bacteriemia. The overall rate of catheter-related complications in patients with acute leukemia was not higher than in patients with solid tumors.