Little is known about the contribution of indoor molds to the symptoms of asthma and/or rhinitis in children monosensitized to molds. We aimed to investigate the effect of indoor mold spore concentrations on daily symptoms of asthma and/or rhinitis in children monosensitized to molds. Nineteen children with asthma and/or rhinitis sensitized only to molds recorded their daily symptoms and peak expiratory flow (PEF) values to the diaries, from February 2005 to January 2006. In this study period, indoor mold concentrations were measured monthly from the living rooms/bedrooms. The median indoor mold concentration was 37.5 CFU/m(3). Most commonly recovered indoor molds were Cladosporium (26.4%), Penicillium (24.7%), and Aspergillus (7%). Significant correlation was not found between indoor mold concentrations and daily rhinitis score (r = -0.021, p = 0.932), daily asthma score (r = 0.155, p = 0.554), daily morning PEF (r = -0.056, p = 0.475), and evening PEF (r = -0.057, p = 0.471). The effect of indoor molds is not evident on the symptoms of our patients with asthma and/or rhinitis monosensitized to molds.