To assess the efficacy and safety of amphotericin B colloidal dispersion (ABCD), 82 patients with proven or probable aspergillosis who were treated in clinical trials with ABCD were compared retrospectively with 261 patients with aspergillosis who were treated with amphotericin B at six cancer or transplant centers from January 1990 to June 1994. The groups were balanced in terms of underlying disease; ABCD recipients were younger and more likely to have preexisting renal insufficiency than were amphotericin B recipients (40.7% vs. 8.7%, respectively), and amphotericin B recipients were more likely to be neutropenic at baseline than were ABCD recipients (42.5% vs. 15.9%, respectively). Response rates (48.8%) and survival rates (50%) among ABCD-treated patients were higher than those (23.4% and 28.4%, respectively) among amphotericin B-treated patients (P < .001 for both comparisons). Renal dysfunction developed less frequently in ABCD recipients than in amphotericin B recipients (8.2% vs. 43.1%, respectively; P < .001). Multivariate analysis revealed that treatment group was the best predictor of response, mortality, and nephrotoxicity (ABCD: relative risk [RR] = 3.00, P = .002; RR = 0.35, P < .001; and RR = 0.13, P = .001; respectively). This retrospective study suggests that in the treatment of aspergillosis ABCD causes fewer nephrotoxic effects than amphotericin B and the efficacy of ABCD is at least comparable with that of amphotericin B.