In the study population, 21% of the 2392 acromegalic patients initially followed in 25 tertiary endocrinology centres were lost to follow-up. At their last follow-up visit, 30% were uncontrolled, 33% were receiving medical therapy and 53% had residual tumour. Of the 362 traced, 62 had died and 77% were receiving follow-up elsewhere; the leading reason for abandoning follow-up was that they had not been informed that it was necessary. Our analysis of the questionnaires suggests that they were not receiving optimal follow-up.