The aetiology of achalasia is unknown, but it has been suggested that it is congenital in origin and associated with such disorders as infantile pyloric stenosis or Hirschsprung's disease. Another reported association has been with Hodgkin's disease. A survey of 126 patients with achalasia, and their first degree relatives was undertaken to record the prevalence of infantile pyloric stenosis, Hirschsprung's disease and Hodgkin's disease. The prevalence of motor neurone disease and diabetes, which can be associated with motility disorders of the oesophagus, were also recorded as a measure of the efficiency of the questionnaire. None of the 126 patients with achalasia suffered from pyloric stenosis, Hirschsprung's disease, Hodgkin's lymphoma or motor neurone disease. There was no increased frequency of these disorders amongst first degree relatives. There appears to be no common aetiology for aganglionic bowel disease, and no obvious association between Hodgkin's disease and achalasia. Diabetes is seen with the expected frequency amongst patients with achalasia and their relatives, indicating the adequacy of the questionnaire.