We conducted a retrospective study of corneal ulcers that had been managed on the Cornea Service at Wills Eye Hospital in 1988 and 1989. Forty-four percent (51 of 116) of the ulcers were associated with contact lens use. Pseudomonas was the most often isolated organism (25 of 116, 22%) and was most frequently associated with cosmetic soft contact lenses (16 of 25, 64%). Ulcers associated with disposable contact lenses (five cases) were similar to those associated with conventional extended wear myopic lenses (15 cases). Pseudomonas was the predominant organism with both disposable (four of five, 80%) and conventional extended wear lenses (nine of 15, 60%). Staphylococcus aureus (19 cases) and Staphylococcus epidermidis (19 cases) were the next most frequently isolated organisms and usually occurred in ulcers not associated with contact lenses (29 of 38, 76%). Ulcers were treated 3.3 times more often in people using extended wear than in those using daily wear myopic lenses. Disposable contact lenses have not eliminated the problem of corneal ulcers associated with extended wear contact lenses.