Recently, new beta-lactam antibiotics, such as imipenem/cilastatin (IMP) with an unusually broad antibacterial spectrum and especially an adequate P. aeruginosa activity, have introduced the possibility of using prospective agent as empiric management of febrile granulocytopenic patients. We randomized 83 febrile neutropenic cancer patients for a prospective evaluation of two regimens: IMP versus piperacillin plus amikacin (PA). Both patients groups were similarly distributed with regard to age, sex, primary diagnosis and degree of granulocytopenia. More than 20% of the 74 evaluable patients had bacteraemia. The overall response rate for clinically or microbiologically documented infections was 90% in the IMP regimen versus 76% in the PA regimen, but statistical difference was not achieved. All bacteraemias in the IMP group but only 60% in the PA group were cured, however statistical difference was not achieved. IMP had to be discontinued in only one patient and the most common side effects were nausea and vomiting; no seizures were noted. Nephro- and ototoxicity, skin rash and bleeding have been the major side effects requiring drug discontinuation in 6 patients treated by PA. In conclusion, these data suggest that IMP used alone is safe and as effective as the combination of P plus A for the management of febrile granulocytopenic patients with haematologic malignancies. Further studies on a larger number of patients are needed to confirm these findings.