To evaluate the histopathologic changes after an inferior oblique marginal myotomy with local injection of triamcinolone, an inferior oblique marginal myotomy was performed in 14 white rabbits and they were divided into 2 groups, one group with a local injection of triamcinolone and the other group without triamcinolone injection after a myotomy. At the postoperative one month, an edema of the muscle fibers and an infiltration of the inflammatory cells were observed and at postoperative three months, a fibrous tissue ingrowth around the muscle fibers and an atrophy of the muscle fibers were found and those changes were less prominant in the group with triamcinolone injection. The local injection of triamcinolone after the inferior oblique marginal myotomy would help in decreasing the fibrous tissue ingrowth and the formation of the scar tissue, thus it could be used in augmenting the effect of the inferior oblique marginal myotomy.