A total of 170 febrile episodes in neutropenic patients with cancer were randomly assigned to be treated with piperacillin-amikacin or ceftazidime-amikacin. The overall response rates were similar in both groups (68 and 65%, respectively). Response rates for clinically or microbiologically documented episodes were 54.5% for piperacillin-amikacin and 58.8% for ceftazidime-amikacin. Response rates for gram-negative bacillary infections were 65 and 73%, respectively. There was also no difference for gram-positive infections (31 and 50%, respectively). The toxicities were also comparable and consisted of skin rashes, hypokalemia, and diarrhea. Vancomycin was added if the fever persisted 72 h after the beginning of therapy; it increased the response rates to 94% when used with piperacillin-amikacin and 92% when used with ceftazidime plus amikacin. Our results suggest that the combinations show similar global efficacies in the treatment of febrile episodes in cancer patients.