Deep fungal infection was diagnosed in 42 patients (a rate of four per 1000) treated during a one-year period between 1988 and 1989 at the Surgical Clinic in Würzburg. Most occurred in association with damage to intra-abdominal hollow organs. Diagnosis of deep fungal infections is difficult and only histological identification provides definite proof. However, often the decision to treat has to be made on the basis of the clinical picture and the physician's subjective assessment. Combination treatment with amphotericin B and 5-fluorocytosine is still the current recommendation but the introduction of the azole antifungal agents appears likely to bring about a change. A trial of fluconazole showed it to have clear advantages over combination treatment, being effective, well tolerated and easily administered.