PURPOSE To evaluate the effect of covering the sclera with conjunctiva during surgical treatment of pterygium on the rate of postoperative complications, cosmetic outcome, and risk of recurrence. METHODS A comparative, prospective clinical design was used. The study population consisted of 371 consecutive patients with unilateral primary advanced pterygium. All underwent bare sclera technique for pterygium excision. At completion of surgery, topical mitomycin C 0.02% was applied for 5 minutes. In the first 189 patients (group A), the conjunctiva was sutured to the sclera 2 mm from the limbus. The next 146 patients (group B), the conjunctiva was sutured at the limbus, covering the whole scleral postexcision defect. In the last 36 patients (group C), the conjunctiva remained unsutured to the sclera. The patients were followed for complications, cosmetic outcome, and recurrence for 26 months. RESULTS After 26 months, 12 patients in group A (6.35%), 10 in group B (6.85%), and 9 in group C (25%) had recurrent pterygium. There were no cases of acute drug toxicity or scleral melting. Treatable delen were noted in 2 patients in group A (1.05%), 2 (1.36%) in group B, and 9 (25%) in group C. The cosmetic appearance was much better in group A than in groups B and C. CONCLUSIONS Leaving the whole sclera uncovered in pterygium surgery places patients at high risk of complications and recurrence. There is no difference in complications and recurrence between covering the whole sclera with conjunctiva and leaving 2 mm bare, although the latter yields a more esthetic outcome.