On the basis of the close anatomical interdigitation between the longitudinal-oriented frontalis muscle and the horizontal-oriented orbicularis oculi muscle (OOM), frontalis OOM (FOOM) flap was developed to treat blepharoptosis. Retrospective study during an 11-year period, 66 patients with 81 poor levator function ptotic eyelids accepted FOOM flap shortening (65 lids; 80.2%) or double-breasted FOOM flap advancement (16 lids; 19.8%) to correct blepharoptosis. There were 51 (77.3%) patients with unilateral ptosis and 15 (22.7%) patients with bilateral ptosis. Severity of blepharoptosis included severe type in 72 (88.9%) lids, moderate type in 5 (6.2%) lids, and mild type in 4 (4.9%) lids. The underlying etiology included congenital origin in 43 (65.1%) patients, involutional change in 19 (28.8%) patients, and neurologic origin in 4 (6.1%) patients. Marginal reflex distance 1 and lid slit distance improved from -1.6 (2.0) to 3.3 (1.2) and 3.2 (2.0) to 7.2 (1.4) mm, respectively, after operation. The postoperative outcome includes good results in 54 (81.8%) patients, fair results in 10 (15.2%) patients, and poor results in 2 (3.0%) patients. The undercorrection or recurrence rate is 14.8%, and secondary revision rate is 11.1%. Positive Hering law is 17.6% among patients with unilateral ptosis. Overall patients' satisfaction rate is 95.1%. Both FOOM flap shortening and double-breasted FOOM flap advancement are effective to treat poor levator function blepharoptosis. Double-breasted FOOM flap advancement is highly recommended because of the more natural contour and minimal lagophthalmos postoperatively, because of the maximal preservation of OOM.