An 88-year-old man with mutilating mucosal leishmaniasis (ML) involving septal perforation, with granulomas in the pharynx and larynx, was treated with oral miltefosine, 50 mg three times/day for 28 days. Miltefosine, an antineoplastic agent, is considered an alternative option for the treatment of ML, showing efficacies of 75-92% in Bolivia, Brazil, and Argentina. The patient denied having previous cutaneous (CL) leishmaniasis, and no CL lesions were recognized by physical examination. Parasites obtained from mucosal lesions were identified by cytochrome b gene sequencing as Leishmania guyanensis. Clinical cure was observed 2 months posttreatment, and no evidence of reactivation was observed in the 3-year follow-up. Adverse effects such as nausea, loss of appetite, and epigastric pain were experienced during treatment with miltefosine. There is a need for improved access to miltefosine in leishmaniasis-endemic areas of Latin America and a greater awareness of ML and its treatment among physicians working in endemic countries.