Electron-microscopic examination of conjunctival and corneal biopsies from six apparently healed trachomatous patients demonstrated chlamydiae in situ. Nine previously trachomatous patients were submitted to the same biopsies; all biopsies were positives. After two months specific anti-chlamydial treatment, we observed the same result before anterior segment surgery. Nevertheless surgery was performed without consequences except for the two corneal grafts which failed. We must ask for two questions: how long chlamydial particles persist in trachomatous tissue? What is the real efficacy of topical anti-chlamydial drugs?