The opening base wedge osteotomy is a safe and useful surgical alternative for correction of moderate to severe hallux valgus deformities with substantial metatarsus primus varus. The authors combine the modified McBride bunionectomy with a proximal first metatarsal opening base wedge osteotomy. Osteotomy stabilization was achieved without bone grafting with a titanium fixation plate specifically designed for opening proximal osteotomies. To assess outcomes achieved by the use of this fixation device, we reviewed the records of 18 procedures (16 patients). Preoperative and postoperative weight-bearing radiographs were measured to compare changes in the following radiographic variables: intermetatarsal angle 1-2, hallux valgus angle, the first metatarsal protrusion distance, and the Seiberg Index. The mean follow-up duration was 11 months (range, 6-17 months). The median intermetatarsal angle decreased by 9 degrees (range, 2 degrees- 15 degrees), the hallux vakgus angle decreased by 13.5 degrees (range, 0 degrees-56 degrees), and the change in first metatarsal protrusion distance was +2.6 mm (range, -0.8 to 6.6 mm), and all of these changes were statistically significant (P <=.001). The preoperative to postoperative change in the Seiberg Index was not statistically significant (P =. 17). In regard to the American Orthopaedic Foot and Ankle Society Hallux Metatarsophalangeal-Interphalangeal score, the postoperative scores were statistically significantly higher than the preoperative scores (P <.001). Complications included 2 (11.11%) recurrences, and 1 (5.56%) case of deep vein thrombosis. Fourteen patients (16/18 feet, 88.89%) reported satisfaction with the surgical results. Level of Clinical Evidence: 4 (The Journal of Foot & Ankle Surgery 48(4):420-426, 2009)