Introduction: Total neoadjuvant therapy (TNT) is increasingly becoming the standard of care for locally advanced low rectal cancer (LARC). Large scale randomised trials show improved disease-free survival and increased rate of complete pathologic response in TNT patients compared to standard neoadjuvant therapy. However, TNT significantly increases time to surgery. Case: A 32-year-old male with LARC developed a malignant large bowel obstruction (LBO) during induction chemotherapy as part of TNT. His tumour had been endoscopically non-traversable at diagnosis; however he had no history of obstructive symptoms. He underwent an emergency diverting sigmoid loop colostomy and recovered without incident, after which he completed neoadjuvant chemotherapy and chemoradiotherapy. Pathology from resection returned as T3N0 adenocarcinoma with near complete tumour regression (TRG 2) and negative margins (R0). He is currently in remission. Discussion: LBO during neoadjuvant therapy for LARC is seldom reported. Management is complicated by immunosuppression from systemic therapy, as well as interruption to neoadjuvant therapy. Endoscopic non-traversability and stricturing appearance on MRI appear to predict LBO during neoadjuvant therapy. Upfront diversion may be considered in high-risk asymptomatic patients; however few obstruct, and diversion may delay systemic therapy causing poorer tumour resectability. Patients who develop malignant LBO during neoadjuvant therapy do not appear to have poorer treatment response based on current limited data. Induction chemotherapy could increase risk of obstruction in at risk patients due to delays to locally targeted therapy, however further studies are needed.