BACKGROUND On the basis of studies in ethnically diverse populations, it appears that the best strategy for prevention of infections is screening of all women aged 25 years or younger. OBJECTIVE The goal was to determine screening criteria in an ethnically and socioeconomically homogenous population with low prevalence of genital chlamydia infection. METHODS Women (N = 1198) attending two family planning clinics were screened for and surveyed for risk factors. Data were analyzed with multivariate logistic regression. RESULTS The overall prevalence of infection was 3.5%. Risk markers for the infection included marital status, number of sex partners, and age. Screening women aged 25 years or younger would have identified 28% of all chlamydial infections, while screening all women aged 30 years or younger would have identified 83% of infections. CONCLUSIONS Because of its feasibility, age appears to still be the best screening criterion. However, extension of the screening to include women up to 30 years of age should be considered.