This study used results from a cross-sectional survey of parents of 3- to 5-year-old children with asthma to assess the frequency of self-reported home environmental conditions that could contribute to worsening asthma and examined the relationship between these factors and the child's asthma morbidity. Participants were 149 parents drawn from the two largest agencies that provide subsidized preschool childcare services in East and Central Harlem, inner-city communities with high prevalence of asthma. The sample represented 77% of eligibles determined by a validated case-identification instrument. Data were collected on demographics, symptoms, medication use, Emergency Department visits and hospitalization, and environmental conditions in the home. One or more of these home environmental conditions were reported by 92% of participants. Controlling for other environmental conditions and demographics, associations were found between self-reported presence of moisture or mildew on ceilings, walls, or windows and higher frequency of hospitalizations for breathing-related problems (OR = 3.31; 95% CI 1.62-6.75), frequent episodes of wheezing (OR = 3.25; 95% CI 1.8-6.0), and higher frequency of night symptoms due to asthma (OR = 2.19; 95% CI 1.4-3.41). Having a carpet or rug in the child's bedroom or the living room was also associated with hospitalizations (OR = 3.23; 95% CI 1.53-6.8), and male gender was marginally associated with the frequency of night symptoms (OR = 1.51; 95% CI .95-2.4). Asthma is prevalent in the Head Start population, and exposure to home environmental conditions that may worsen asthma is common in the socially disadvantaged populations served by Head Start programs.