Introduction: Brachial plexus reconstruction with free functional muscle transfers (FFMT) has become a reliable tool in the armamentarium of brachial plexus surgeon (Potter and Ferris, The Journal of hand surgery, European volume, 2017, 42,693-9). The successful execution of performing FFMT relies on favourable motor nerves for coaptation and appropriate vessels for microvascular anastomoses. Due to shared traumatic aetiology, subclavian and axillary vascular injury (SAVI) can coexist with the brachial plexus palsy and may pose a surgical dilemma with such FFMT execution. Method: We performed a retrospective study of 100 consecutive patients who presented to our hospital with brachial plexus injury over a 10-year period. Patient records were reviewed for concomitant SAVI and subsequent treatment that was required for both vascular (SAVI) and brachial plexus injuries (BPI). Results: Concomitant BPI and SAVI occurred in 27% of patients. Open injuries predicted significantly higher rates of SAVI as well as complete plexus palsy. Complete plexus palsy was associated at a higher rate in the SAVI group compared to the non-SAVI group. Conclusion: Coexistence of SAVI and BPI is frequent. Complete plexus palsy and SAVI are more common in open injuries in this study. Complete plexus palsy is the most common indication for FFMT in BPI. Surgical execution of FFMT is more challenging in the setting of previous SAVI and requires careful consideration of the microsurgical plan. We recommend that all patients with previous SAVI or potential need for FFMT in this setting undergo vascular imaging at the time of acute injury and prior to any free flap reconstructive procedures.