We evaluated the safety and efficacy of tobramycin and gentamicin sulfate ophthalmic solutions in the treatment of patients with bacterial infections of the conjunctivas. In this double-masked study involving 66 patients, the two aminoglycosides were found to be equally safe and effective, although the in vitro data suggested that tobramycin may be more efficacious against Pseudomonas infections. Staphylococcus aureus and S. epidermidis were the most frequent isolates from the infected eyes (59.8% and 20.6%, respectively).