Thyroid ophthalmopathy frequently causes significant upper- and lower-eyelid retraction. This is not only cosmetically disfiguring, but also causes the cornea to be exposed so that a lid-correcting procedure becomes necessary. We used the Mueller ectomy technique with mechanical disinsertion of the levator muscle of the upper eyelid, as described by Putterman et al. in 1972, and operated on ten patients with thyroid ophthalmopathy. By means of the Mueller ectomy and mechanical disinsertion of the levator muscle of the upper eyelid, the eyelid was lowered by 5.0 mm compared with the preoperative findings (measured as the distance between the edge of the upper eyelid and the center of the pupil). In 3 cases the postoperative result was a temporal upper eyelid flare that required operative correction in one case; in one case a ptosis resulted postoperatively. Transconjunctival Mueller ectomy with mechanical disinsertion of the levator muscle of the upper eyelid gives good cosmetic and functional results in patients with significant upper-eyelid retraction. The transconjunctival approach avoids external scar formation and leaves the external lid structures intact so that a revision can be performed by an external lid incision.