Mycetoma is a chronic, granulomatous, subcutaneous, inflammatory lesion caused by true fungi (eumycetoma) or filamentous bacteria (actinomycetoma). Mycetoma commonly affects young people between 20 and 40 years old. The most common affected site is the foot. The characteristic clinical triad is tumefaction, draining sinuses and discharging grains. We report a healthy 31-year-old male, with a 6-year history of a progressive inflammatory tumor associated with sinus tracts and granules on his left sole. Actinomycetoma was suspected. The clinical diagnosis was confirmed by microbiological and histopathological study. Polymerase chain reaction and DNA sequencing identified Actinomadura madurae. To our knowledge, this is the second case of mycetoma reported in Chile. Our report emphasizes the need to consider this diagnosis in patients with chronic granulomatous disease associated with sinus tracts, fistulas and grains.