BACKGROUND: Scalenus syndrome is a collection of symptoms as the consequences of nerve and vascular compression within the scalene triangle. However, the entity has long been forgotten in publications and is difficult to recognize. The diagnosis of scalenus syndrome is mainly based on clinical findings. The Ali Shahab score is a new scoring system, generated based on clinical symptoms of scalenus syndrome. AIM: In this study, we presented a case series of scalenus syndrome patients who were diagnosed and decide to be managed surgically based on Ali Shahab score. We also reported post-operative outcomes following scalenectomy in our series. METHODS: This was a case series including patients with scalenus syndrome in Gatot Soebroto Army Hospital, Indonesia, and Siloam Asri Hospital, Indonesia, between 2016 and 2021. The diagnosis of scalenus syndrome was made based on Ali Shahab score with a value of more than 7. All patients were performed scalenectomy to decompress the stenotic subclavian artery and brachial plexus from surrounding fibrotic tissue. Eligible subjects were assessed for sex, side of symptoms, pre-operative and post-operative Ali Shahab score, and post-operative outcome. RESULTS: We included 96 patients with scalenus syndrome in this case series. Most of the included patients were male (59.4%) and experienced scalenus syndrome on the right side (76%). The average pre-operative Ali Shahab score in our series was 7.12 ± 0.48 and the post-operative score was 0.11 ± 0. Regarding post-operative outcomes, more than half of the patients experienced symptoms reduction with 38.5% of patients experiencing complete resolution of symptoms following scalenectomy. CONCLUSION: The application of the Ali Shahab score may be used as a diagnostic tool and decision of surgical management for scalenus syndrome patients. Decompression of the subclavian artery and releasing brachial plexus from surrounding fibrotic tissue can improve clinical symptoms in scalenus syndrome patients.