Background: Routine chlamydia screening is not readily available at all college campuses. Objectives: To assess the prevalence of Chlamydia trachomatis among asymptomatic college students and to compare chlamydia positivity by selected demographic variables. Methods: Analysis of demographical data collected on 789 students who volunteered for a urine screening of C. trachomatis and Neisseria gonorrheae infections at 10 colleges in Alabama, Georgia, and Mississippi. Results: The median age was 20 years. The chlamydia prevalence among all students was 9.7%. Students under the age of 20 years were 66% more likely to be infected than were older students (95% CI 1.01-2.73). Younger female students were 92% more likely to be infected than were older female students (95% CI 1.03-3.59). Conclusions: The chlamydia prevalence was higher in younger college students; more screening efforts and increased awareness are needed to reduce the prevalence of chlamydial infections among students. Copyright © 2008, American Sexually Transmitted Diseases Association.