• A multicenter, double-masked, randomized clinical investigation was conducted comparing 0.3% ofloxacin and 0.3% tobramycin for topical treatment of external ocular infection. One drop ( 1.35 μg) of either test solution was instilled six times daily for 2 days and thereafter four times daily for the next 8 days. At the day 3 to 5 follow-up examination, the severity of signs and symptoms based on a clinical summary score of 10 key variables was reduced from baseline values significantly (P<0.5) more with ofloxacin (−6.4±4.37; mean±SD) than with tobramycin (−4.78±3.13); by day 11, the difference between the groups was no longer significant. At days 3 to 5 and day 11 examinations, clinical, microbiologic, and overall improvement rates were similar, with no significant differences seen between the groups. Ofloxacin was found as effective, safe, and comfortable as tobramycin in patients with external ocular infection and may provide earlier symptom relief.