A system for serial surveillance cultures and serological tests for diagnosis of disseminated fungal infections (FI) was evaluated retrospectively in 14 bone marrow transplantation (BMT) patients with autopsy proven FI (11 with Candida albicans and 3 with Aspergillus fumigatus) and 14 control BMT patients without FI. The 2 groups did not differ with regard to clinical features. Serial cultures for candida from various sites were more often positive in the FI group than in the controls (p less than 0.001). Consistently negative cultures were never seen in the FI patients (p less than 0.05). Positive conventional blood cultures or cultures of specimens from bronchoscopy were suggestive of FI before death in 6/14 of the patients with FI. No blood cultures were positive among the controls. Sequential serum samples taken before death in 7 patients with systemic candidiasis, 3 with invasive aspergillosis, and 12 control patients, were tested retrospectively for diagnostic candida and aspergillus antibody titers and free circulating candida mannan. The serological tests gave evidence of FI in 9/10 patients with FI and in half of the controls (p less than 0.05). In 8/10 cases with FI, serological tests became positive before a positive blood culture or a clinical suspicion of FI. With a prevalence of 7.5% of FI at our clinic, the predictive values for positive and negative was 100% and 97% for the antigenemia test and 14% and 100% for the ELISA test for IgA antibody against C. albicans mannan. Our data suggest that a rational use of surveillance cultures and serological tests may aid in an earlier diagnosis of FI in BMT patients.