We report on three patients with multiple myeloma who developed drug-induced pneumonitis 1-2(1/2) months following maintenance (post autologous transplantation) chemotherapy with CDEP (cyclophosphamide, dexamethasone, etoposide, cisplatin) and 6-20 months after exposure to carmustine (BCNU) 300 mg/m(2), used in combination with melphalan 140 mg/m(2), as pre-transplant conditioning regimen. All patients had either a proven (two) or suspected (one) fungal pneumonia and were treated with liposomal amphotericin B. Dyspnea, fever and cough were the prominent clinical symptoms, while air-space disease with ground glass appearance was seen radiographically. Histologic features typical for drug-induced lung injury were detected. All patients had a dramatic, clinical and radiographic response to a brief course of corticosteroids. Although CDEP-induced pneumonitis appears to be a rare complication, its early recognition and prompt treatment, as well as its possible association with preceding fungal infection may have important clinical implications.