Objective: Although testing for Chlamydia trachomatis is encouraged and increasingly practiced at sexually transmitted disease (STD) and family planning clinics, patterns of testing and follow-up in other settings are not well described. To begin to address these issues, we performed a chart review of patients with a positive laboratory test for C. trachomatis at a major university medical center. Methods: Chart review of medical records for all patients with positive laboratory tests for C. trachomatis during calendar year 1996. Results: Of 326 patients with positive tests, 95% were female and 5% were male. Median age was 22 for females and 25 for males. Most positive C. trachomatis test results were from the emergency room (ER)/walk-in clinic (55%) or patients receiving obstetric/gynecologic (OB/GYN) care (31%). While most C. trachomatis tests performed were on patients who had symptoms, patterns of treatment varied between sites. Fifty-seven percent of ER/walk-in patients received empiric antibiotics at the initial visit versus 36% of patients under OB/GYN care. Among patients with positive screening tests seen in the ER/walk-in clinic, 32% of patients had no treatment documented versus 14% of OB/GYN patients. Four percent of women with positive tests who did not receive therapy at the time of their initial evaluation developed pelvic inflammatory disease in the interval between testing and return to the medical center. Conclusions: Of the patients with positive chlamydial screening tests, the proportion not treated was similar to that found in studies performed in STD clinics.