PURPOSE: To present two cases of conjunctival lesions exhibiting the Splendore-Hoeppli phenomenon, each with different immunohistochemical findings. DESIGN: Interventional case reports. METHODS: Two young males with conjunctival lesions underwent biopsy. Demographic data and timing of biopsy were extracted from the charts. The biopsy specimens were formalin fixed and paraffin embedded for light microscopy. Immunohistochemical staining using the peroxidase method was carried out on each for IgG, IgM, IgA, the C3 component of complement, and eosinophilic major basic protein. main outcome measures: Presence of positive or negative staining for the various antigens. RESULTS: Both biopsy specimens exhibited the Splendore-Hoeppli phenomenon, a morphologically unique process consisting of an amorphous, eosinophilic material surrounded by epithelioid histiocytes, multinucleated giant cells, lymphocytes, and eosinophils. Two staining patterns were seen. One revealed predominately immunoglobulin deposition, whereas the other revealed primarily eosinophilic major basic protein. This is the first instance we are aware of in which eosinophilic major basic protein was the predominate finding in an ocular specimen. CONCLUSION: The composition of Splendore-Hoeppli phenomenon material varies and may be related to various factors, including timing of biopsy and prior treatment. © 2005 by Elsevier Inc. All rights reserved.