Conjunctival provocation tests (CPT) were performed in 65 respiratory allergic patients, 24 of them with a clinical history of allergic conjunctivitis and 41 who had never complained of allergic conjunctivitis, to assess the role of the conjunctiva as a target organ. The usefulness of CPT and RAST to identify symptom-related and symptom-unrelated allergen in 51 patients sensitized to two allergens but only symptomatic to one of them was also studied. Conjunctiva was found to react in a similar way to skin in patients with and without clinical conjunctivitis. CPT was positive for both symptom-related and symptom-unrelated allergens in 33 of the 51 pluri-sensitized patients. Nevertheless, in the 18 patients showing positive CPT to only one allergen, agreement with clinical data was generally found. Thus CPT appears to be a useful test in the evaluation of atopic sensitization in patients reactive to a single allergen, but not in the identification of clinically relevant allergens in individuals who are skin or RAST positive to multiple agents.