Data on all discharges from hospitals in Scotland have been recorded since 1961 as the Scottish Hospital In-Patient Statistics and examination of these data has permitted analysis of the incidence and mortality trends from acute pancreatitis. The number of discharges recorded has increased 11-fold in males from 69 patients/year in 1961 to 750 patients/year in 1985, and fourfold in females from 112 patients/year to 484 patients/year respectively. This increase has occurred particularly amongst young and middle-aged males (20-59 years) and in elderly females (over 60 years), the most marked increases occurring in the health boards of the 'central belt' area of Scotland. Mortality rate did not show a corresponding change, increasing only two-fold in males from 15 patients/year to 30 patients/year and in females from 29 patients/year to 37 patients/year. As a consequence the case mortality rate has fallen from 17.8 per cent over the period 1961-65 to 5.6 per cent over the period 1981-85. An apparent increase in the incidence of acute pancreatitis may be inferred from these data, much of which is thought to be due to improved accuracy in diagnosis.