Systemic mycosis constitute a serious threat for the patient with granulocytopenia. The most important causative agents are Candida spp., Aspergillus spp. and, to a lesser extent, Cryptococcus neoformans, Mucoraceae and Pseudoallescheria boydii. Treatment of such infections with amphotericin B is difficult, because of the many side-effects of this medicine, such as hypotension, fever, shivering, thrombophlebitis, nephrotoxicity, renal tubular acidosis, hypokalaemia, anaemia and thrombocytopenia. In addition, the efficacy of amphotericin B in the treatment of proven mycotic infections in granulocytopenic patients is not very great. Itraconazole is a new, oral antifungal agent which is active in vitro and in animal experiments against both Candida and Aspergillus. In patients without granulocytopenia, itraconazole appeared to be effective in the treatment of deep Candida and Aspergillus infections. On the basis of the above data, a randomized comparative investigation was carried out unto the efficacy of amphotericin B and itraconazole in the treatment of systemic mycoses in neutropenic patients.