Clinical characteristics of allergic asthma due to inhalation of cockroach antigens have been reported sporadically in the literature. To assess the patterns of bronchial response in cockroach asthma we performed bronchial provocation tests (BPT) with cockroach extract in 25 asthmatic patients who had positive skin test with this extract. Of 25 patients, 23 had cockroach-specific-IgE-antibodies. Seventeen subjects presented only immediate asthmatic reaction, five patients had dual response (immediate + late), and one patient developed only late asthmatic response. BPT were negative in two patients who did not have cockroach-specific-IgE-antibodies. These results indicate that BPT with cockroach antigen is a very specific test for cockroach asthma. It shows immediate, dual and late responses, and correlates well with the presence of specific IgE antibodies against this allergen.