Our previous experiences with liposomal amphotericin have suggested that it is an effective antifungal agent in neutropaenic patients with relatively few toxicity problems compared with conventional amphotericin B. This interim report presents early data from a single-centre, prospective randomised study with AmBisome. The study was designed to compare the early initiation of AmBisome in febrile neutropaenic patients (with haematological malignancy) with its later use, and to examine the efficacy and toxicity of different doses of this antifungal agent, Our experiences from the first 137 patients recruited (n = 200) are discussed, in addition to some of the difficulties that have arisen during the study.