The speech of 17 Parkinsonian patients was evaluated before and after the administration of L-DOPA therapy. A significant difference was demonstrated after treatment for voice quality, articulation, and pitch variation, but not for rate of speech. Amount of speech improvement correlated significantly with amount of physical improvement. Although age and duration of disease may exert some influence on speech change, the results suggest that these factors do not reliably predict the response. After 4 years of L-DOPA therapy, three out of four patients demonstrated additional improvement or the same degree of speech improvement.