Asthma is a very common respiratory allergic disease in Taiwan. The aims of this study were to investigate the allergen-sensitized profile and its relationship with serum total IgE levels in allergic asthmatic children in Taiwan. Moreover, the number of allergens to be tested for the most efficient and effective diagnosis of allergic diseases was also examined. Total IgE and IgE specific for a panel of common aeroallergens were assayed in 200 serum samples of asthmatic children using Pharmacia CAP system (Pharmacia, Uppsala, Sweden). House dust mites Der p (Dermatophagoides pteronyssinus), Der f (Dermatophagoides farinae), and Bt (Blomia Tropicalis) had the highest sensitized rates at 82.5%, 82.0%, and 72%, respectively. Candida albican (14.0%) and Bermuda grass (8.0%) were the most common sensitized fungus and pollen in our subjects, respectively. The accumulated sensitized rate (10%) for pollens was lower than those of fungus (21.5%) and house dust allergens (84%). The average serum total IgE of the allergen-negative asthmatic children (n=30) was significantly lower than that of children with at least one allergen sensitized asthma (n=170) (377.9 +/- 123.6 vs. 1117.8 +/- 235.7 IU/ml, p<0.05). The level of total IgE was significantly correlated with the concentrations of mite-specific IgE antibodies, but not with the numbers of allergen sensitized. In addition, the detection rate was 84% when the 4 most common allergens (Der p, Der f, Dog dander, and cockroach) were tested, similar to the result after testing for all 12.