Carcinoma that develops in chronic ulcers, wounds, burn scars and fistulas is known as Marjolin's ulcer. It occurs primarily as a squamous cell carcinoma and rarely as basal cell carcinoma. Marjolin's ulcer represents 2% to 5% of all squamous cell carcinomas of the skin. We present a 60-year-old male patient with chronic ulceration on the right leg. The ulceration appeared 15 years before at the localization of the burn scar following an injury and was treated for years as a chronic venous ulcer. After sudden enlargement of the ulcer, biopsy confirmed it to be invasive squamous cell carcinoma. Ultrasound and computed tomography revealed a metastatic squamous cell carcinoma in the inguinal lymph node. After complete excision of the tumor and inguinal lymph node dissection, the patient was under supervision of the surgeon and oncologist because of tumor relapse on the skin and lymph node. This case should serve as a reminder to practitioners to perform biopsy of every ulcer that fails to heal or when other risk factors for venous ulcers are missing, in order to avoid delay in diagnosis and complications.