Block failure is a significant challenge in regional anaesthesia, leading to inadequate analgesia, patient discomfort, and prolonged surgical times. This article explores the causes, prevention, and management of failed peripheral nerve blocks, focusing on rescue techniques. Causes of block failure include patient factors (comorbidities, anxiety), operator experience, anatomical variations, tourniquet pain, and inappropriate block selection. Prevention strategies include proper nerve identification, optimal local anaesthetic choice, and assessing block efficacy preoperatively. Management options include distal rescue blocks, surgeon-administered local anaesthetic infiltration, IV sedation, and conversion to general anaesthesia in severe cases. A structured approach improves block success rates and patient outcomes.