Peripheral entrapment neuropathy is a rare complication of rhabdomyolysis and lacks successful treatment. In this article, we report a case of sciatic neuropathy caused by piriformis rhabdomyolysis which was successfully treated with ultrasound-guided sciatic nerve hydrodissection. A 27-year-old male patient with left buttock pain and left lower limb weakness received ultrasound-guided nerve hydrodissection via injection of dexamethasone and 5% dextrose water into the area surrounding the left sciatic nerve. After injection, the patient's pain and left lower extremity weakness subsided. In conclusion, although peripheral entrapment neuropathy due to rhabdomyolysis is rare, early diagnosis and treatment using ultrasound-guided nerve hydrodissection may yield favorable clinical outcomes.