Chest radiography and abdominal ultrasound are two widely used diagnostic imaging techniques in Western societies. However, little is known about the frequency of these examinations and its determinants. The aim of this descriptive study was to provide detailed information on the number of chest radiography and abdominal ultrasound examinations by age, gender, referring physician and ethnicity. We used data of approximately 3,000,000 sick fund insured persons of the Health Insurance Company Agis in The Netherlands from 1999 to 2003. We calculated annual numbers and corresponding 95% confidence intervals for different age, gender and ethnicity categories. The mean age of the population was 38+/-22 years and 46% were male. Chest radiographs were ordered in 130 per 1000 persons per year and abdominal ultrasound examinations in 39 per 1000 persons per year; these frequencies did not change noticeable over the five-year period. Chest radiography was performed more often in males (156 vs. 109 per 1,000 persons/year in females; p < 0.05) and abdominal ultrasound more often in females (43 vs. 34 per 1000 persons/year in males; p < 0.05). Frequencies were highest in persons aged 70-79 years. Compared to medical specialists, general practitioners more frequently referred younger patients and females, especially for abdominal ultrasound. Up to the age of 60 years the frequencies of both chest radiography and abdominal ultrasound were higher in Turks and Moroccans compared to other persons. In conclusion, this study showed marked differences in the frequencies of chest radiography and abdominal ultrasound according to age, gender and ethnicity in The Netherlands.