Introduction: Tendo-Achilles (TA) is one of the main tendons utilized for every movement of the lower limb. Rupture of TA leads to severe disruption of overall mobility and leads to difficulty in doing daily routine activities. The purpose of this prospective study was to observe the functional outcome of gastrocnemius fascial turn down flap with flexor hallucis longus (FHL) augmentation for chronic TA tear. Materials and methods: Tendo-Achilles rupture was diagnosed in all patients either by clinical or radiological means (most of them were type II or type III according to KUWADA classification). Preoperative functional scores (modified RUPP, FADI, FAAM, VAS) were documented. All 13 patients were treated surgically by gastrocnemius fascial turn down flap with FHL augmentation. All surgeries were performed by the same surgeon. The standard postoperative protocol was followed in all patients. Patients were followed up regularly at 3 months, 6 months, 1 year, and 2 years postoperative for functional outcome score. Results: The results were statistically analyzed by paired T-test for evaluating improvement in pre- and post-intervention periods. Functional outcome scores showed a significant improvement with FAAM score was improved from 30.84 ± 2.9 to 76.23 ± 3.98 (p < 0.001), FADI 40.92 ± 3.15 to 85.2 ± 4.04 (p < 0.001), modified RUPP score at 2 weeks postoperatively was 3.07 ± 1.18 which at 2 years of follow-up improved to mean score 22.77 ± 3.45 (p < 0.0001). VAS preoperatively value of 7.77 ± 1.01 improvised to 1.85 ± 0.99 at 2 years’ follow-up (p < 0.01) showing a significant decrease in overall pain. Conclusion: Functional outcomes show turn down flap with FHL augmentation as a good procedure for chronic TA rupture. Proper rehabilitation and wound care is the mainstay for good outcomes. Wound dehiscence is, however, a challenge that needs special care for providing good outcomes. Level of evidence: III