Heavy back packs carried for prolonged durations can cause different musculoskeletal and neurological problems especially in the untrained and physically vulnerable individuals. They can cause postural disorders, gait abnormalities, muscular strains, pains and injuries to the brachial plexus and nerves resulting in significant morbidity and at times permanent disability. We report a case of brachial plexus injury in a young soldier wearing back pack for prolonged period. He developed weakness and pain in right shoulder which was not relieved with rest and analgesics. On examination he had weakness in deltoid, biceps and scapular muscles along with numbness in axillary nerve area. Brachial plexus injury (upper trunk) was suspected and confirmed by electrodiagnostic evaluation. His baseline investigations were normal. He was advised rest and avoidance to lift heavy weight. He was managed with electrical muscle stimulation for weak muscles, strengthening exercises and analgesics. He responded well to the treatment and had minimal residual weakness at the end of the six weeks’ treatment

Back pack palsy should be suspected in people carrying back packs and presenting with pain, weakness and numbness in the upper limbs. It can be prevented by education in the use of back packs, its weight limits, physical fitness and frequent breaks with changing positions.