Background: Adjunctive intraoperative mitomycin C increases the success of glaucoma filtering surgery, but also the postoperative complications. This is the first report of scleritis after its use. Patients: In five patients, scleritis developed 3 to 24 weeks after inferior trabeculectomy with mitomycin C. The onset was characterized by acute pain, redness of the eye, and decreased vision. Three patients had anterior scleritis and two had posterior scleritis. Infection or bleb leakage was not seen in any patient. Results: All patients responded to a course of topical steroids and oral ibuprofen or prednisone. Conclusion: Anterior and posterior scleritis may complicate the use of topical mitomycin C during trabeculectomy. Prompt diagnosis and treatment reverses the inflammation, maintaining the success of the surgical procedure.