Bacterial keratitis continues to be a serious problem in developing countries. The authors studied 881 patients who had undergone penetrating keratoplasty (total of 947 procedures) from January 1983 to March 1986 at the King Khaled Eye Specialist Hospital, Riyadh, Saudia Arabia. All patients were followed for at least 6 months. Clinical evidence of bacterial keratitis developed in 113 (11.9%) eyes with penetrating keratoplasties in 108 patients. The causative organisms among those patients included: Streptococcus pneumoniae, 29 (26%); Staphylococcus epidermidis, 24 (21%); Pseudomonas aeruginosa, 13 (12%); Staphylococcus aureus, 5 (4%); Hemophilus influenzae, 5 (4%); Moraxella spp, 5 (4%); alpha-hemolytic streptococcus, 5 (4%); and other bacteria, 27 (25%). In addition, postoperative epithelial defects that required hospital admission for treatment developed in 21 (2.2%) patients. Herpetic keratitis developed in three (0.3%) patients and fungal keratitis developed in 1 (0.1%). Statistically significant predisposing risk factors included: trichiasis (P less than 0.0001), epithelial defects (P less than 0.0001), soft contact lens wear (P less than 0.0001), and eroding sutures (P less than 0.0001). The authors believe that the incidence of postoperative bacterial keratitis can be minimized or avoided by appropriate selection of patients for penetrating keratoplasties as well as good preoperative and postoperative management of associated ocular conditions.