Recurrent peptic ulcer usually develops as the result of an ill-advised or poorly executed operation. The commonest surgical error is an incomplete vagotomy. Diagnosis is made best by endoscopy. Mandatory investigation includes determination of serum gastrin and calcium, and measurement of basal and maximal acid output. Management is surgical and depends on the initial ulcer operation. Decision-making is aided by the Hollander insulin test, the secretin infusion test and occasionally by a technetium scan. There is no place for procedures that do not reduce acid output. Emergency treatment of a complication should be followed by full investigation and the appropriate operation. Recurrent gastric ulcer should be treated by gastrectomy and excision of the ulcer.