This case report records a unilateral perineal hernia in a 7year-old female donkey. The donkey had a history of unilateral swelling lateral to the left vulvar lip and difficulty in defaecation. Upon palpation, the swelling was painless, soft and reducible. Ultrasonography revealed a hyperechoic hernia sac containing dilated nonmotile bowel with homogenous hypoechoic contents. Primary herniorrhaphy was performed after repositioning of the herniated bowel. The donkey made an uneventful recovery with no recurrence or complications for 6 months of available follow-up. In conclusion, perineal hernia should be considered in the differential diagnosis of perineal swellings in donkeys. Clinical examination, ultrasonography and surgical exploration are valuable for definite diagnosis of perineal hernia in donkeys. Surgical herniorrhaphy was successful in correcting the problem in this case.