BackgroundAt smoking except of current person the non-smoked people of that environment are suffering much the effect of which would be considered to as “passive smoking”. In result of smoking in offices, bar and nightclub, gers and apartments the air of current internal environment would be contaminated through toxic and cancer originating combinations. In regard of our country, Mongolia has entered into the International anti-tobacco convention and there are in progress certain arrangements toward reduction of smoking, study of its negative effects and smoking habit. Unfortunately there is deficit of researches determining the content of tobacco nicotine in offices and public places, form one hand. From other hand there is lack of scientific arguments and facts proving negarive effects of passive smoking and its influences upon environment, people and children. Therefore, we have conducted present research work.GoalThe main objectives this study were to assess secondhand smoke exposure in bar employees and determine air and hair nicotine concentrations.Materials and MethodsWe have carried out present research work according to instant method by involving 10 bars and entertainments and placing 2 air monitors in each bar. There were involved 5 persons from current places, questioned and taken hair samples of 50 employees. At determining nicotine content of air and hair we have used the method of gas chromatography.ResultsTheir average age was 22.3. As we have taken sample in 10 bars and entertainments of Ulaanbaatar city the average content of nicotine counted 14.78 μg/mg. It is 2-3 times more than other countries. The nicotine content in hair of smoking staff is at average 18.06 μg/mg and in hair of non-smoking staff at average 4.24 μg/mg. The more are business hours, the much increases the content of nicotine in hair.Conclusions:This study found very high levels of exposure to secondhand smoke in bars and nightclubs from Ulaanbaatar, Mongolia. Of high concern, time weighted air nicotine concentrations measured in this study were markedly higher than concentrations measured in bars and nightclubs from several African, American, Asian and European countries. Implementing a comprehensive smoke-free legislation that protects workers and customers from exposure to secondhand smoke is urgently needed in Mongolia.