Comprehensive speech examinations of 10 equally affected subjects with moderate, treated Parkinson’s disease were performed before and 4 weeks following initiation of treatment with selegiline (deprenyl), with other drug therapies unchanged. Forty different measures relating to the speech processes of respiration, phonation, resonation, articulation and prosody were examined to measure changes in performance due to selegiline. Significant improvements were noted for 8 of the 40 measures, with these improvements relating to the speech processes of articulation and respiration. The potential interactive effects of comedication are discussed. In addition, previously undescribed comprehensive speech characteristics of moderate Parkinson’s disease are presented and discus