A study was conducted to determine the prevalence of fungal infection in cancer patients warded at the Hospital Kuala Lumpur. There were 138 patients included in the study: 74 with haematological malignancies and 64 with solid tumours. Serological results showed that for candidiasis 16/138 (11.5%) and 10/134 (7.5%) were greater than 1:8 reactive for antigen and antibodies respectively. For aspergillosis, 29/122 (23.8%) sera were antigen reactive. Only 1/133 each (O.SO/o) was reactive for cryptococcal antigen and antibody. The types of malignancies, the age of the patient, a history of neutropenia, the duration of the cancer, the number of courses of chemotherapy or radiotherapy were not predictive of fungal infections. In view of the high serological evidence of fungal infection and the lack of a reliable diagnostic test, empirical antifungal treatment must be considered in all febrile neutropenic cancer patients.