In the present study we assessed the prevalence of sensitizations to Blomia in our environment. Perennial climatological conditions in the Canarian Islands facilitates the habitat to mites. The Blomia is found in tropical and subtropical homes of Europe, USA and Asia like the Dermatophagoides. We have designed a transversal and prospective study on 100 patients who consulted our Unit for the first time. A Prick-test for the common allergens, including Blomia Kulagini, and in vitro determination of total and specific IgE to Dermatophagoides Pteronyssinus and Farinae, was performed in those patients showing the same or higher levels than class 3 CAP System RAST-Fesa against Blomia Tropicalis. Results achieved in our environment and our patients are the following: 1. Prevalence of sensitizations to BK in patients who consult for the first time is 50%. 2. The specific IgE immunologic response to BK is 56% (45 patients). 3. Scarce correlation in the papule areas and specific IgE levels between BT and DTP (p = 0.22020); BT and DFA (p = 0.09063). Table VI. Fig. I and II. 4. These results and previous studies of allergenization suggest poor crossed reactivity between Blomia and Dermatophagoides. 5. We think that Blomia is a new etilogic agent of the allergic respiratory disorders in our environment and therefore it should be included in the standard set of allergens from a diagnostic and therapeutical point of view. We keep studying its identification and count in dust samples from our homes, as well as the crossed reactivity, by RAST inhibition, with other acari.