Background. Patients with hematologic malig-

nancies and a history of an invasive fungal infec-tion are considered to be at high risk of suffering reactivation of the infection during subsequent intensive chemotherapy. Patients and Methods. From January 1993 to September 1996, nine patients with a hematologic malignancy and previous invasive pulmonary aspergillosis (IPA) or Pseudallescheria boydii pneu-monia and five with invasive candidiasis received further intensive chemotherapy (n=3) or a bone marrow or peripheral blood stem cell transplant (n=11) four days to 13 months (median three months) from the start of therapy for the fungal infection. Five patients with IPA and all five with invasive candidiasis showed complete or good par-tial radiologic resolution of the infection with the primary antifungal therapy given, which was con-tinued before, during and after the period(s) of subsequent neutropenia. Results. Twelve of the 14 patients showed no signs of progression or reactivation of the fungal infection during therapy, while two patients with active IPA died of progressive aspergillosis shortly after an allogeneic transplant. A review of the liter-ature revealed that in both types of infections the risk of reactivation and dissemination appears low after achieving clinical and radiologic signs of response, which takes several weeks or months before proceeding to further antileukemic therapy. Interpretation and Conclusions. Despite a lack of definite evidence, administration of an active anti-fungal drug before, during and after the period of neutropenia apperas to be useful. In IPA residual masses, nodules or cavities in the lung usually con-tain viable invasive fungal elements and should be resected whenever possible. On the other hand, the risk of reactivation and progression of an active fungal infection during intensive chemo-radiotherapy is very high, and novel therapeutic strategies seem to be warranted in this setting