The Finnish Tobacco Act has restricted smoking in public places since 1976, and in 1994 the Act was amended to include workplaces as well. In 2000, the Tobacco Act will be expanded further to restaurants. In Finland, the exposure of clients and employees to the vapor phase environmental tobacco smoke (ETS) in restaurants has not been systematically studied before by measuring ETS markers in indoor air. However, in these establishments the concentrations of ETS are expected to be much higher than in other workplaces. Gaseous nicotine and 3-ethenylpyridine were used as indicators of ETS in three different types of restaurants. Mean concentrations of nicotine ranged from 1.4-42.2 micrograms/m3 and 3-ethenylpyridine 1.4-6.3 micrograms/m3. In addition, concentrations of total volatile organic compounds (TVOC), CO and CO2 were measured and concentrations were 183-2215 micrograms/m3, 0.9-3.1 mg/m3 and 600-880 ppm, respectively. The concentrations of ETS markers were highest in discos and nightclubs and lowest in restaurants. The concentrations of total volatile organic compounds were highest in discos and nightclubs, especially when smoke generators were used.