Keratoacanthoma (KA) is a rapidly growing cutaneous neoplasm deriving from the hair follicle. KA usually occurs to sun-exposed sites and can cause local tissue destruction, Excisional surgery is recommended for the majority of KA cases. However, an excision can cause significant cosmetic or functional problems, and older patients with comorbid conditions are not good candidates for surgical management. In these cases, intralesional methotrexate (MTX) offers a less invasive treatment option of acceptable cosmetic results. Herein, we report a case of KA successfully treated with intralesional MTX injection in an elderly male patient. A 79-years old male presented with an asymptomatic, solitary, 5 x 4 cm-sized, erythematous mass with ulceration on the scalp for three years. The patient received ablative laser therapy for the lesion at a local clinic several times, but it recurred. Histological examination showed symmetrical relatively sharply circumscribed proliferation of keratinocytes with central horn plug. At the periphery, epidermis extends over tumor cupping. There were minimal nuclear pleomorphism and mitoses. Based on the clinical and histopathological findings, the diagnosis of KA was made. The patient was treated with intralesional injection of MTX at a concentration of 12.5 mg/ml in 1 to 2 weeks interval for four months. The size of the lesion significantly decreased after 10 times of MTX injection