Irincotecan (CPT-11 [Camptosar] has a board range of antitumor activity. Extensive preclinical and early clinical work has demonstrated its activity against many tumor types--head and neck, esophagus, stomach, pancreas, liver, colon/rectum, kidney, lymph nodes, ovary, uterine, cervix, sarcoma, melanoma, acute and chronic leukemia, mesothelioma, and cancers of unknown primary site. Most of the phase II and III trials have focused on colorectal and other gastrointestinal, non-small-cell lung, and cervical cancers (discussed elsewhere in this monograph). This article presents preliminary results of studies exploring the use of irinotecan in lymphoma, leukemia, and breast, pancreatic, ovarian, and small-cell lung cancers. In all of these studies, the number of patients enrolled is small, drug doses and schedules differ (often within the same case series), and little information is available on response duration and overall survival. Nevertheless, irinotecan has shown reproducible if at times modest activity in almost all of the diseases in which it has been studied. Future research should be directed at conducting well-designed clinical trials of irinotecan alone and in combination with other agents.