Purpose Surgical repair of the Achilles tendon is a common procedure in cases of acute rupture. Open Achilles tendon surgery with a traditional extensile approach is most often performed in the prone position, but this can lead to numerous complications. The mini-open approach for repair in the supine position may avoid the risks of the prone position. The purpose of this study is to compare perioperative outcomes and differences in cost between patients undergoing acute Achilles rupture repair with mini-open approach, incision of approximately 3 cm, in the supine position versus traditional approach in the prone position. Methods Patients who underwent surgical repair of acute Achilles rupture at a single institution were retrospectively identified using Current Procedural Terminology (CPT) code 27650. Complication rates and the total cost charged to the insurance companies of both the supine and prone groups were calculated. Results A total of 80 patients were included for analysis, 26 supine and 54 prone. The difference in average total time in the operating room was statistically significant. The prone position took approximately 15% more time (118.7 minutes) compared to the supine position (100 minutes) (p = 0.001). While not statistically significant, the total cost for the supine group ($19,889) was less than the for the prone group ($21,722) (p = 0.153) Average postoperative pain score, infection rate, dehiscence rate, sepsis rate, and deep vein thrombosis (DVT) rate were also similar between the two groups. No patient in either group experienced re-rupture of the Achilles tendon within the first year of primary repair. Conclusion The mini-open approach in the supine position may be advantageous in the repair of acute Achilles rupture in that it reduces total time in the operating room and total cost while maintaining positive patient outcomes. Prospective clinical studies are warranted to validate these assessments.