This study examined the association of residential environmental factors with respiratory symptoms and asthma in 2,290 fifth graders in Taipei, Taiwan. A self-report survey questionnaire elicited experiences of respiratory symptoms, disease history, and characteristics of residential environmental factors from schoolchildren. The proportion of schoolchildren having physician-diagnosed asthma was 9.8% and suspected asthma was 16.1%. The proportions of having respiratory symptoms in the past 12 months ranged from 9.8% for wheezing without a cold to 40.5% for exercise-induced cough. Higher proportions of boys had non-exercise-induced respiratory symptoms, physician-diagnosed asthma, and suspected asthma than girls (p < 0.05). Exposure to odoriferous chemical vapor was significantly associated with all seven respiratory symptoms considered in the study (p < 0.05). After adjusting for confounding factors including residential districts, gender, diagnosed allergy, and parental history of respiratory symptoms, odoriferous chemical vapors, gas leaks, dehumidifier use, presence of cockroaches at home, and leaky water/water puddle at home were significantly associated with the proportions of physician-diagnosed asthma or suspected asthma of the schoolchildren. The adjusted odds ratio (aOR) of physician-diagnosed asthma was 2.35 (95% confidential interval = 1.45-3.82) for odoriferous chemical vapor. The aOR of suspected asthma measure was 2.14 (95% CI = 1.40-3.26) for odoriferous chemical vapor. Odoriferous chemical vapor was the major risk factor of respiratory illness in the residential environment of schoolchildren in Taipei. Other household risk factors included gas leaks, dampness, and cockroaches at home.