Chlamydia trachomatis (Ct) infections are sexually transmitted, often asymptomatic, and may lead to reduced fertility in women. Available sensitive detection methods on urine and effective single-dose treatment have made home-based screening for Ct infections feasible. In Swedish surveillance data we interpretated increasing chlamydia trends while using more sensitive tests. In a home based screening study in the Netherlands, 15-29 year old men and women were invited by Municipal Health Services. Response was 41%, and Ct prevalence was 0.6% in rural areas and 3.2% in very highly urbanised areas. Nationwide systematic screening is not indicated in the Netherlands and targeted approaches are a better option. We developed a prediction rule based on risk factors which is a promising tool for selective Ct-screening at population level. A reasonable discriminative ability of the rule was shown in population based data from Amsterdam and an outrea