The effectiveness of intraoperative administration of mitomycin C and the occurrence of postoperative complications have been evaluated in 30 white patients with one recurrence of pterygium. The authors employed the 'bare-sclera technique' and, intraoperatively, placed in the episcleral space for 3 min a sterile sponge soaked in a 4% mitomycin C solution. The control group (30 patients with one recurrent pterygium) underwent only surgical excision. Statistical analysis performed using the chi-square test showed a significant (p = 0.024) reduction of recurrences of pterygium in the group treated intraoperatively with mitomycin C. No heavy side effects occurred during the follow-up period. Mitomycin C, administered intraoperatively, may be considered an effective treatment to improve the success rate after surgical excision.