Objective: We sought to determine if specific molds were found in significantly higher concentrations in the water-damaged homes of asthmatic children compared with homes with no visible water damage. Methods: The mold concentrations in the dust in asthmatic children's bedrooms in water-damaged homes (N = 60) and control homes (N = 22) were measured by mold-specific quantitative polymerase chain reaction. Results: Two molds, Scopulariopsis brevicaulis and Trichoderma viride, had significantly (P < 0.05) higher concentrations in asthmatics' homes compared with control homes and three other molds (Penicillium crustosum group, Stachybotrys chartarum, and Wallemia sebi) had P values < 0.1. Conclusions: A relative moldiness index was developed to predict the likely development of asthma in water-damaged homes in Cleveland.