The objective of this study is to offer basic scientific data to support policy decision-making for the improved control of nitrogen dioxide(NO2) and nitrous acid(HONO) in residence. The survey on concentration of NO2 and HONO in 20 houses in Seoul and Daegu was performed from January to February, 2013. Average NO2 concentrations in the kitchen, living room, and room were 25.7±7.7ppb, 24.3±8.5ppb, and 19.6±5.6ppb, respectively. Also, average HONO concentration were 3.6±1.0ppb, 3.1±0.9ppb, and 3.1±0.9ppb, respectively. NO2 and HONO concentration in kitchen were significantly higher than the concentration in the living room and room(p<0.05). Concentration ratios of HONO/NO2 were ranged to 0.070–0.277 for indoor air and 0.004–0.161 for outdoor air. Indoor HONO/NO2 ratios were higher than the outdoor HONO/NO2 ratios. Keywords : Nitrogen dioxide, Nitrous acid(HONO), kitchen, living room, HONO/NO2 ratio