In a 12-month prospective study incorporating four neighbouring district general hospitals, 228 patients required a total of 236 admissions with intestinal obstruction. The aetiological factors included adhesions 75 (32 per cent), malignant disease 61 (26 per cent), strangulated hernias 59 (25 per cent), volvulus 10 (4 per cent), acquired megacolon 6 (3 per cent), pseudo-obstruction 4 (2 per cent), faecal impaction 6 (3 per cent) and miscellaneous 15 (6 per cent). The peak incidence for obstruction due to adhesions, malignant disease and strangulated hernias each occurred in the eighth decade. Surgery was performed within 48 h of admission in 29 per cent adhesive obstructions (22), 30 per cent obstructions due to malignant disease (18) and 68 per cent strangulated hernias (40)--bowel resection rates in these three groups were 13.5, 50 and 29 per cent, respectively. The overall mortality was 11.4 per cent (26 deaths) and postoperative mortality was 12.3 per cent (19 deaths). During the 12-month study period, 228 patients required a total of 2993 inpatient hospital days as a result of intestinal obstruction. Postoperative adhesions have become the commonest cause of intestinal obstruction but strangulated hernias and intra-abdominal malignant disease still account for 50 per cent of all cases and mortalities. Obstruction due to strangulated hernias and intra-abdominal malignant disease typically occurs in the elderly age group where a more aggressive policy of elective surgical intervention is likely to be associated with increased postoperative morbidity and mortality.