We examined seven patients with Acanthamoeba keratitis. All patients had a history of soft contact lens use. Predisposing factors included use of homemade saline, hydrogen peroxide disinfection, a history of improper lens care, and swimming with contact lenses. Currently recommended medical therapy, including topical propamidine isethionate and dibromopropamidine isethionate, miconazole, Neosporin, corticosteroids, and systemic ketoconazole, was used in all patients. Five patients have undergone penetrating keratoplasty for progressive primary Acanthamoeba keratitis (four patients) or recurrent infection (one patient) after maximal medical therapy. Two patients who began medical therapy less than three weeks after the onset of symptoms have done well. Early diagnosis of Acanthamoeba keratitis appears critical for successful medical therapy. Penetrating keratoplasty continues to have a central role in the management of more advanced cases that are unresponsive, or only transiently responsive, to medical therapy.