We studied 126 children with allergic illness in Instituto Nacional de Pediatria. We applied cutaneous test to determine the early, late and dual response. The results were 68% for the early response, 6% late response and 26% dual response. The allergens more frequently found in the early and late response were Dermatophagoides pteronyssinus, Dermatophagoides farinae and house dust. Approximately the third part of the children studied presented late cutaneous response (dual response more isolated late response). It is important to make the evaluation of the late response in patients with allergy disease for a good etiologic diagnosis.