Introduction: Adult acquired flat foot is means a fallen or lost medial longitudinal arch that may or may not be symptomatic. This complex foot deformity involves changes of the ankle and foot that affect the entire lower extremity and gait cycle. Maintaining the longitudinal arch of the foot involves dynamic and static structures. Objective: The aim of this study is to evaluate the efficacy of use of calcaneal osteotomy with or without tendon transfer for management of early stages of adult acquired flat foot to illustrate advantages and disadvantages of this procedure in progress of the disease. Patients and Methods: A prospective study on twenty patients with twenty feet 20 patients older than 18 years with adult acquired flexible flatfoot stage 2. Patients were evaluated pre and postoperatively using AOFAS score. Patients followed up for a minimum of 6 month with the mean follow up period were 9.90 month (range 6- 15 months). The duration of symptoms before the operation ranged from 11 month to 18 month with an average 13.55 (SD was 2.305). Results: AOFAS score improved from mean 53.05±4.904 preoperative to 88.80±3.205 postoperatively. Clinically, all patients have satisfactory level of function. Radiologically, the mean AP radiographs improved from 18.50±8.036 preoperatively to 6.85 ± 5.112 postoperatively. The mean lateral radiographs improved from 19.40 ± 7.437 preoperatively to 8.40 ±7.366 postoperatively. Complications include 3 cases with sural nerve injury, 1 case with persistence pain & swelling and 1 case developed talonavicular nonunion. Conclusions: While MDCO is a reliable corrective method in all cases with hind foot valgus deformity. FDL transfer should be done only for cases of PTTD grade 2 and lateral column lengthening for cases of forefoot abduction. Medial column procedures are suitable for cases with forefoot supination (cotton osteotomy), if there is instability or arthritis fusion is the best. We recommend further study with large sample size and longer term follow up to confirm these results.