We compared quantitative histologic counts of ten subjects with vernal conjunctivitis to counts of 15 subjects with contact lens-associated giant papillary conjunctivitis and to counts of 15 normal subjects. Both vernal conjunctivitis and contact lens-associated giant papillary conjunctivitis subjects had abnormalities of mast cells in the epithelium, and eosinophils and basophils in epithelium and substantia propria. No normal individuals had these abnormalities. An additional 28 subjects with ocular inflammatory conditions had tissue evaluation for abnormalities of mast cells, eosinophils, and basophils. A few eosinophils were found in four subjects. The histologic abnormalities of vernal conjunctivitis are shared by contact lens-associated giant papillary conjunctivitis but not by conjunctival inflammation in general. Vernal conjunctivitis and contact lens-associated giant papillary conjunctivitis may represent different subtypes of a general category of conjunctival abnormality characterized by giant papillae.