For many years, NO2 has been regarded as one of the elements among indoor air pollutants of urban homes, leading to increased public concerns on this gas. For the purpose of preparing the fundamental data for the evaluation and control of health effect relevant to NO2 levels, authors measured the indoor (kitchen, living room, bedroom) and outdoor NO2 levels categorized by the type of house(apartment, detached dwelling) and cooking fuel(L.P.G., briquette) in the winter and summer, and surveyed the variables(kitchen ventilation, family size, parental smoking) may effect the indoor NO2 levels. The level of NO2 was measured by Palmes tube, and this survey was carried out at 110 homes in the Pusan area from October 1984 to September 1985. The obtained results were as follows: 1) The mean indoor and outdoor NO2 level in winter and summer, respectively, was 0.029+/-0.012 ppm and 0.022+/-0.012 ppm in the kitchen, 0.022+/-0.009 ppm and 0.018+/-0.010 ppm in the living room, 0.017+/-0.008 ppm and 0.016+/-0.010 ppm in the bed room, and 0.021+/-0.007 ppm and 0.016+/-0.007 ppm outdoors. 2) In the category of the type of house and cooking fuel, the highest mean indoor and outdoor NO2 level in the winter was in apartments using briquettes, and in the summer, the highest level was in apartments using L.P.G. 3) In the category of the type of house, the mean indoor and outdoor NO2 level in the winter and summer was higher in the apartment group compared to detached dwelling. 4) In the category of the type of cooking fuel, the mean indoor and outdoor NO2 level in the winter was higher in the briquette group, and in the summer, the L.P.G. group was higher. 5) In the category of the kitchen ventilation, family size, parental smoking and asthma attack history of children, there was an insignificant difference in the indoor NO2 levels.