The air pollution due to tobacco smoke and its effects on employees were investigated in 44 work-rooms. For that purpose the concentration of CO, NO, Nicotine and the Particulate Matter were determined and 472 employees were interviewed about annoyance and irritations. The mean values of the concentrations of the components due to tobacco smoke are: CO = 1.1 ppm, NO = 32 ppb, Nicotine = 0.9 micrograms/m3, Particulate Matter = 133 micrograms/m3. The use of an indicator is discussed. One third of the employees qualifies the air wit regard to smoke at work place as bad. 40% of the interviewed persons are disturbed by smoke. One quarter of th persons indicates eye irritations. The majority of the employees support a separation of the rooms in smoking and non-smoking areas. This seems to be the most appropriate preventive measure for the protection of the nonsmokers at work.