Carboplatin, an analog of the antitumor drug Platinol, was selected for clinical evaluation on the basis of its experimental antitumor and toxicologic profile in animal models. Described in this review is a detailed summary of selected preclinical data accumulated on carboplatin as well as data obtained concomitantly using Platinol. The predominant result gleaned from the experimental antitumor data is that of comparability between the two compounds, a finding which we feel best reflects the emerging clinical data. With respect to the preclinical toxicology, carboplatin was found to be less nephrotoxic and less emetic than Platinol. This pattern of toxicity for carboplatin appears to be substantiated in the clinical setting.