Background: Little is known about the prevalence of depression in older patients consulting their general practitioner. Aim: To estimate the prevalence of major and minor depression in older GP attendees. Design: Cross sectional two-stage screening design. Setting: Seventeen GPs in urban and 41 GPs in rural settings. Methods: Data of The West Friesland Study were used. Five thousand, six hundered and eight-six GP attendees of 55 years and older filled in the Geriatric Depression Scale - 15 items as a screening instrument for depression (response 62%). Of those screened positive on the GDS-15, 846 (77.5%) were interviewed using the Primary Care Evaluation of Mental Disorders (PRIME-MD). A random sample (n = 102) scoring below the threshold of the GDS-15 was interviewed to estimate the proportion of false negatives. Results: Major depression was prevalent in 13.7% and minor depression in 10.2% of the patients. Depressed patients were older (mean difference 0.7 years; p = 0.037), more often female (OR 1.3; p < 0.001) and lived more often in urban districts (OR 1.5; p < 0.001). Patients with major depression were younger (mean difference 1.9 years; p < 0.001) and more often female (OR 1.4; p = 0.026) than those with a minor depression. Only 22.9% of the patients with a major depression were treated with antidepressants. Conclusion: Depression in older GP attendees is a very common health problem. Further research should focus on identifying those groups of patients with high risk of persistence of depression. This could help to focus the limited resources available in general practice to those patients in whom treatment is most urgently needed.