Background: Allergic conjunctivitis is an in ammatory disease which involves the conjunctiva, its physiopathology is a type I hypersensitivity (IgE mediated). It is related to the sensitization to indoors and out- doors aeroallergens. Clinically it is classi ed as seasonal or perennial. It presents as ocular pruritus, conjunctival hyperemia, epiphora and photophobia. Objective: To determine the frequency of sensitization to aeroallergens in patients with allergic conjunctivitis, seasonal and perennial, who attend the Allergy and Clinical Immunology Department at Mexican General Hospital Dr. Eduardo Liceaga. Material and method: A transversal and descriptive study was made in patients with seasonal and perennial allergic conjunctivitis. After in- formed consent, we obtained a complete clinical evaluation, laboratory studies and skin tests for aeroallergens. We determined the frequency of sensitization to those aeroallergens. Results: We found sensitization most frequently to pollens such as Quercus, Alnus and Fraxinus, followed by Dermatophagoides spp. We had predominantly female patients of the second and fourth decades of life. Conclusions: Allergic conjunctivitis is a pathology frequently associated with allergic rhinitis. The most frequently involved allergens in this study were pollens and house dust mite.