Tobacco smoke was confirmed as a human carcinogen by many research results. Because many adolescents stay long time in the PC game room, they are exposed to much of tobacco smoke. To evaluate the effect of passive smoking in the PC game room, airborne nicotine concentrations in 2 PC game rooms in Sung-nam city and urinary cotinine concentrations were measured for 20 adolescents. And the subjects were interviewed for duration and time in PC game room and smoking pattern. Subjects are composed of each of 10 smokers(5 males and 5 females) and 10 nonsmokers(5 males and 5 females). They stayed for three hours in the PC game room without smoking. Concentrations of nicotine in smokers and nonsmokers were 129.72 $mu$g/$^3$ and 99.99 $mu$g/m$^3$, respectively. Urinary cotinine concentrations were increased as time goes on after exposure to nicotine and showed maximum value at 9.45 hours after nicotine exposure and were 32.21 and 110.66 $mu$g/L for nonsmoker and smokers. The more using time and frequency in PC game room, the higher urinary cotinine maximum concentration and the longer using duration, also the more increase urinary cotinine concentration. Urinary cotinine has a tendency to increase by passive smoking. Therefore, it is recommended that the effective control for indoor air quality and extensive research be needed to reduce nicotine concentration by passive smoking in the PC game room.