Liposomal amphotercin B was compared with conventional amphotericin B for empirical antifungal therapy in febrile neutropenic patients in a randomized, double-blind, multicentre trial. Using a composite end-point, the two drugs were equivalent in overall efficacy. However, the liposomal amphotericin B treatment group had fewer proven fungal infections, fewer infusion-related side effects and less nephrotoxicity. Patient data from that study were analysed to compare the pharmacoeconomics of liposomal versus conventional amphotericin B therapy. Itemized billing data from 414 patients were collected and analysed. Hospital costs from first dose were significantly higher for all patients who received liposomal amphotericin B ($48,962 versus $43,183, P = 0.02). However, hospital costs were very sensitive to the cost of the study medication ($39,648 versus $43,048, when acquisition costs are not included, P = 0.4). Using decision analysis models and sensitivity analyses to vary the cost of study medications and risk of nephrotoxicity, the break-even points for the cost of liposomal therapy were calculated to range from $72 to $87 per 50 mg for all patients, and $83 to $112 per 50 mg in allogeneic bone marrow transplant patients. Therefore, the drug acquisition costs and the risk of nephrotoxicity are important factors in determining the cost-effectiveness of liposomal amphotericin B as empirical therapy in persistently febrile neutropenic patients. In a recent randomized double-blind study comparing liposomal amphotericin B at 3 or 5 mg/kg/day with amphotericin B lipid complex (ABLC) 5 mg/kg/day as empirical antifungal treatment in patients with febrile neutropenia, liposomal amphotericin B was associated with less toxicity than ABLC, both in terms of infusion-related reactions and nephrotoxicity. The incidence of study drug discontinuation due to toxicity was: liposomal amphotericin B 3 mg/kg/day, 14%; liposomal amphotericin B 5 mg/kg/day, 15%; and ABLC, 42% (P < 0.001).