The purpose of this research is to study the clinical features and risk factors of various types of allergic conjunctivitis. Four hundred and forty-five patients with a history of itching, foreign body sensation, lacrimation and red eyes were examined, and a skin test was performed and assessed to grade the severity. The mean age of the subjects was 24.5 +/- 16.3 years with female preponderance, except for vernal keratoconjunctivitis. The majority of the patients had perennial allergic conjunctivitis. Ninety-five percent of the patients had associated allergic diseases, especially allergic rhinitis. Sixty-six percent of the patients had a family history of atopy. Most patients had symptoms at night. Symptoms persisted throughout the year and were generally triggered by exposure to house dust. The allergy skin tests to common aero-allergens were positive in 95% of patients tested. Common allergens causing sensitization were house-dust mites, house dust, cockroaches, and grass pollen. Environmental control and avoidance of these allergens should be stressed in the management of these conditions.