A survey of NTT workers regarding smoking control in their workplaces was conducted utilizing a questionnaire administered at the time of routine employee medical examinations. The questionnaire was self-administered and anonymous. Subjects were 1918 men, almost all who were involved in office work in the Tokyo area. Responses were obtained from 1872 (20's and 30's year of age 13.2%, 40's 68.1%, 50's 18.8%) after excluding 106 for incomplete responses. The results were as follows; 1. Of the subjects, 43.4% reported that smoking control was already in effect in their workplace. As for the method of smoking control, smoking restricted to specified places was the most common (31.1%). 2. Of smokers, only 9.8% approved of smoking control in their workplaces, 9.8% were opposed, and 80.1% of smokers reluctantly complied to smoking control in their workplaces. 3. About 60% of subjects, without distinguishing smoking habit, supported smoking restricted to specified areas as the method of smoking control. 4. Over 95% of smokers replied that they can successfully refrain from smoking in prohibited places. 5. For locations where they smoke, smokers listed employee lounge (91.5%), lavatory (83.7%), personal room (75.5%), at own desk (75.3%), reception room (72.7%) and conference room (64.3%). More than half of non-smokers replied that they disapprove of smoking in these places. These results suggest that smoking restricted to only specified places is most appropriate as the method of smoking control in the workplace. However differences exist between smokers and non-smokers as to appropriate designation of smoking areas and non-smoking areas.