BACKGROUND The incidence of acute appendicitis declined in western countries between the 1930s and the early 1990s. The aim of this study was to determine time trends in hospital admissions for acute appendicitis in England between 1989-1990 and 1999-2000, and in population mortality rates for appendicitis from 1979 to 1999. METHODS : Hospital Episode Statistics for admissions were obtained from the Department of Health and mortality data from the Office for National Statistics. RESULTS Between 1989-1990 and 1999-2000, age-standardized hospital admission rates for acute appendicitis decreased by 12.5 per cent in male patients and by 18.8 per cent in female patients. The proportions of admissions that resulted in operation remained stable. Admission rates for non-specific mesenteric lymphadenitis fell. Admission rates for abdominal pain increased between 1989-1990 and 1995-1996, at which time the International Classification of Diseases codes changed. Between 1995-1996 and 1999-2000, admission rates for abdominal pain declined. Analysis of age-specific admission rates for acute appendicitis and abdominal pain from 1989-1990 to 1995-1996 showed that the decline in acute appendicitis could not be accounted for by a change in diagnostic practice. Mortality rates for acute appendicitis remained stable over the study period. CONCLUSIONS Admission rates for acute appendicitis declined over the study period. This decline cannot be explained by reclassification.