Nine cases of Acanthamoeba keratitis not associated with contact lens wear were diagnosed between July 1987 and August 1989. Patients were treated with topical neomycin-polymyxin B-bacitracin (Neosporin) drops alone or in combination with either miconazole nitrate or ketoconazole drops. At the time of data collection four patients were available for follow-up for an average of 4 months; however, four patients were unavailable for follow-up and one is still undergoing treatment. In four patients corneal infiltrates cleared completely with topical medication (Neosporin, two patients; Neosporin plus miconazole, two patients). Simple laboratory methods were found to be adequate for the diagnosis of Acanthamoeba keratitis. Therapy with Neosporin drops can result in resolution of corneal infiltrates due to Acanthamoeba species.