An 8‐year‐old male German Shepherd dog with a history of dyschezia, tenesmus and perineal swelling for 1 month was referred. The dog was known to be unilaterally abdominal cryptorchid. The normally descended testis had been surgically removed a few years ago. On physical examination, a firm, non‐painful, irreducible mass was palpable in the left perineal region. Digital rectal examination revealed rectal deviation, and the pelvic diaphragm was absent on the left. The prostate gland was normal upon palpation. Abdominal radiography revealed that the urinary bladder was present in the caudal abdomen. Based on clinical, laboratory and imaging findings, a diagnosis of perineal hernia was made. Surgical exploration revealed the presence of left spermatic cord torsion in the perineal hernia. The testis was removed, and internal obturator muscle transposition was performed for herniorrhaphy. The dog had an uneventful recovery, and the results of re‐examinations 10 days, 6 months and 12 months later were normal.