Introduction. Subcutaneous rupture of achilles tendon is a frequent trauma and most patients with such pathology are men of working age. Even though it is not difficult to diagnose such ruptures, especially those that need surgical treatment, there are numerous cases when patients come to a surgeon with a big delay. In such cases, the rupture becomes «chronic» or «neglected» and can be no longer treated as an acute rupture. There are many techniques of operative treatment of chronic achilles tendon ruptures, but still there is no consensus on which technique is to be considered the most simple, effective and safe.The aim of this study is to evaluate the effectiveness of using peroneus brevis tendon as a graft for treatment of achilles tendon defects type 3 in Kuwada classification. Will this technique bring good and excellent results that are comparable with end-to-end suture after acute achilles tendon ruptures?Materials and methods. The present study includes 13 patients in which peroneus brevis was used for treatment of neglected achilles tendon rupture (group I) and 18 patients after end-to-end suture after acute achilles tendon rupture (group II). Group I consisted of patients with neglected rupture of achilles tendon that was not previously treated due to various reasons and with a significant defect.Results. Mean surgery duration in group I was 91.9±6.6 (Me — 100) min, in group II — 43.2±2.2 (Me — 45) (p = 0.0001). damaged limb was evaluated using achilles Tendon Total Rupture Score, mean post-op follow up was around 1 year. The results were: group I — 86.6±2.28 (Me — 87), group II — 93.4±1.01 (Me — 94) (p = 0.04). This means, that despite quite high scores in group I, they are still statistically worse than scores after suture of acute rupture in group II. There was no difference in post-operative complication rate between the groups (p0.05). The most common complication for both groups was range of motion restriction in ankle joint. None of the patients had ankle joint instability after surgery.Conclusion. Management of neglected ruptures of achilles tendon type 3 (in Kuwada classification) with peroneus brevis autologous graft is an effective and safe technique, that achieves good and excellent results in treatment of this group of patients, in absolute numbers is comparable to functional outcomes after end-to-end suture of acute achilles tendon ruptures, but statistically demonstrates significantly worse results.