Background: Upper endoscopy is frequently performed, yet there are few published data regarding utilization trends. Such data provide an indication of changes in clinical practice over time and identify subpopulations who may be underexposed or overexposed to the procedure. Methods: Time series data were analyzed for all diagnostic upper endoscopies performed on residents of an Australia state between mid 1988 and mid 1998. Endoscopy rates by age, gender, and patient status (public vs. privately insured) were calculated. Results: In 1997/98 the endoscopy rate was 179 of 10,000. The majority were performed on publicly insured patients and women. Over the decade the rate increased by 128%. Rate increases were not constant across time, age, gender, or patient (insurance) status. The greatest increases occurred in the early to mid 1990s, and in patients less than 65 years of age. There was a greater increase (126%) among women 55 to 64 years of age compared with other age categories for both genders. Rates for publicly insured patients increased more than those for privately insured patients, particularly among individuals in the age range 25 to 34 years. Rates for private patients increased more for women than men (81% vs. 59%). Conclusions: Rates of utilization of endoscopy increased dramatically during the period from 1988 to 1998, particularly during the earlier part of this decade. The cause(s) of the differences in sub-population rates warrant investigation, as do their relationship to patient management and outcomes. These data provide opportunities for international comparisons.