After reviewing the experience of various authors we applied the Basophil Degranulation Test (BDT) in the study of sensitization to Dermatophagoides pteronyssinus, so as to evaluate its diagnostic use. Fifty-five patients with asthma and/or rhinitis and a positive skin test to the mentioned antigen, as well as 20 control subjects were studied. The results demonstrated a sensitivity of 65.5% and a specificity of 80% with an efficiency index of 69.5%. We did not find any significant correlation with the histamine release test (r = 0.236). The data obtained and the proper limitations of the technique led us to consider the BDT to have a limited application in routine allergy diagnosis.