Genital chlamydial infection is a common, sexually transmitted infection that is often asymptomatic, but associated with long term morbidity in a sizeable proportion of women. Early infection can be diagnosed reliably using non-invasive methods and treated effectively with antibiotics. The case for screening in conventional high risk settings ( e.g. genito-urinary medicine and termination of pregnancy clinics) is already clear. Screening in the wider community also needs evaluating if a significant impact on the problem is to be made since chlamydial infection is widely distributed among young, sexually active people who may have little contact with health services. Studies are in progress to assess the acceptability of different screening approaches to women and men in the community and to compare performance of newer diagnostic techniques. The cost-effectiveness of community-based screening in reducing morbidity needs to be evaluated empirically in randomised trials to encourage a coherent, evidence-based screening policy in this country.