We measured the levels of major basic protein and Charcot-Leyden crystal protein in tears from patients with ventral keratoconjunctivitis or miscellaneous inflammatory or noninflammatory ocular conditions, and from normal subjects. Patients with vernal keratoconjunctivitis had significantly increased levels of both proteins in their tears compared with the other subjects tested; levels of major basic protein seemed to correlate with the severity of the disease. The levels of Charcot-Leyden crystal protein paralleled those of major basic proteins.