To evaluate the safety and efficacy of subconjunctival mitomycin C as adjunctive therapy before pterygium surgery. Prospective noncomparative case series. Thirty-six eyes of 36 patients. Thirty-six eyes of 36 patients prospectively received 0.1 ml of 0.15 mg/ml mitomycin C subconjunctivally injected into the head of the pterygium 1 month before bare sclera surgical excision. Recurrence of pterygia. The pterygia resolved in 34 (94%) of 36 eyes, with a recurrence rate of 6% over a mean follow-up of 24.4 months. No wound-healing complication developed in any patient. Subconjunctival mitomycin C is an effective treatment before pterygium excision. Subconjunctival injection allows exact titration of mitomycin C delivery to the activated fibroblasts and minimizes epithelial toxicity.