Previous observations suggest that "pseudoexfoliation of the lens capsule" may be a disease in which cells produce abnormal basement membrane material. Electron microscopic studies indicate that exfoliative material can be produced by cells throughout the anterior segment of the eye. This report describes abundant exfoliative material on the ciliary and iridic epithelia but not on the surface of the lens whose epithelial cells were completely necrotic. Exfoliative material also was observed in the anterior iridic stroma close to a newly formed abnormal endothelial basement membrane, suggesting that exfoliative material may be produced locally within the iris. Furthermore, typical exfoliative material, best considered a filamentous, banded basement membrane with 500-A periodicity, in the wall of a short posterior ciliary artery in the orbit indicates that the exfoliative process is not solely limited to ocular tissues. The term "basement membrane exfoliation syndrome" is proposed for this entity.