Rationale: Chronic exposure to indoor nitrogen dioxide(NO₂) is a public health concern. Over half of US households have a source of NO₂, and experimental data suggests potential for adverse respiratory effects. Objective: To examine associations of indoor NO₂ exposure with respiratory symptoms among asthmatic children. Methods: NO₂ was measured using Palmes tubes, and respiratory symptoms in the month prior to sampling were collected during home interviews of mothers of 728 children with active asthma. All were younger than 12 years; lived at sampled home for at least 2 months; had asthma symptoms or used maintenance medication within previous year. Measurements: Respiratory symptoms (wheeze, persistent cough, shortness of breath, chest tightness). Results: Mean(SD) NO₂ was 8.6 (9.1) ppb in homes with electric ranges; 25.9 (18.1) ppb in homes with gas stoves. In models stratified by housing type gas stove presence and elevated NO₂ were each significantly associated with respiratory symptoms, controlling for age, ethnicity, medication, mold/mildew, water leaks, season of sampling. Among children in multifamily housing, exposure to gas stoves increased likelihood of wheeze (Odds Ratio (OR) [95% Confidence Interval (CI)] 2.27 [1.15,4.47]), shortness of breath (2.33 [1.12,5.06]) and chest tightness (4.34 [1.76,10.69]). Each 20 ppb increase in NO₂ increased both likelihood of any wheeze (1.52 [1.04,2.21])or chest tightness (1.61 [1.04,2.49]), and days of wheeze (1.33 [1.05,1.68])or chest tightness (1.51 [1.18,1.91]). Conclusion: Exposure to indoor NO₂, at levels well below the EPA outdoor standard (53 ppb), is associated with respiratory symptoms among asthmatic children in multifamily housing.