We employed a time series design to evaluate the impact of the 1989 California cigarette tax increase on cigarette consumption in California. Adult per capita consumption data from 1980 to 1990 were analyzed for California and the United States. Trend data indicated a sharp drop in California cigarette consumption coincident with the tax increase. Time-series regression analyses support this observation, and suggest that a 5% to 7% decline in consumption is attributable to the tax increase.