A retrospective analysis was undertaken of the clinical diagnoses of 1594 eyes that underwent penetrating keratoplasty performed in a private-referral corneal practice over a 9-year period, 1980-1988. The seven most common indications for surgery were keratoconus (24.0%), pseudophakic or aphakic bullous keratopathy (21.2%), corneal scarring (13.9%), Fuchs' endothelial dystrophy (12.5%), regraft (8.1%), and herpetic keratitis (5.3%). Keratoconus was the leading indication from 1980 to 1985. From 1985 to 1988, pseudophakic bullous keratopathy became the leading indication and correlates well with known complications associated with closed-loop anterior chamber lenses, which were widely used during the early 1980s. Less frequent indications for penetrating keratoplasty included the following: infectious (nonviral) keratitis (3.5%); acute or chronic ulcerative keratitis (2.7%); interstitial keratitis (1.8%); mechanical trauma (1.5%); other (non-Fuchs') corneal dystrophies (1.4%); congenital opacities (0.8%); and chemical burns (0.5%).