Deprenyl (selegiline) delays the need for levodopa therapy in patients with early Parkinson's disease, but the value of long-term treatment with this type B monoamine oxidase inhibitor remains unsettled. We examined mortality among the 800 patients with early Parkinson's disease who were not requiring levodopa and who were randomly assigned in the DATATOP trial to receive deprenyl, tocopherol, combined treatments, or placebo. Ascertainment of the vital status of subjects in this double-blinded trial was performed prospectively after the initial randomization, during open-label deprenyl, and after a second independent randomization to continue active deprenyl or switch to matching placebo. The study was conducted at 28 academic medical centers in the United States and Canada. After an average of 8.2 years of observation, the overall death rate of our subjects was 17.1% (137 of 800) or 2.1% per year. The mortality rate was unaffected by deprenyl, tocopherol, or combined treatment assignments and was about that expected for an age- and gender-matched US population without Parkinson's disease. Neither deprenyl, tocopherol, nor their combined treatments affected the duration of life in our early Parkinson's disease patients. The deprenyl-related delay in disability that we reported previously was not associated with a deprenyl-related reduction in mortality.