We analyzed all appendectomies in Sweden 1989-1993 (n = 60,306) recorded in the national Inpatient Registry. Our focus was on diagnostic accuracy, incidence rate of appendicitis, perforative appendicitis, and length of stay by day of admission and hospital category. The incidence rate of appendectomy decreased by 9.8% in women compared to 4.1% in men. Since the number of patients with an end diagnosis of appendicitis remained almost constant, diagnostic accuracy increased each year. This was more pronounced in women than men, seen in all hospital categories, and was higher for those admitted during periods of low capacity (weekends/ holidays). Perforated appendicitis did not increase. Duration of hospital stay decreased continuously, especially among the oldest. We found no indications of an increased frequency of complications, such as increases in the incidence rate of perforations or in the length of stay.