Twenty-six investigational anticancer drugs formerly supplied by the National Cancer Institute are no longer available due to the lack of requests for their use in clinical trials. This report examines the data on these drugs to determine how well they were clinically evaluated. Generally, the studies are incomplete, and 34% of the compounds have not been studied beyond phase I trials. Clinical pharmacology data were not obtained for most of the drugs. In addition, the information available for drugs that did undergo phase II trials is grossly inadequate and does not permit a confident decision to withdraw them from investigational use. Instances of "hints" of activity and interesting drug properties are cited to stimulate further study. Finally, a list of compounds scheduled for future termination is given within the framework of this analysis to provoke thought toward obtaining more phase II data before these drugs fall into disuse.