Marjolin's ulcers are malignancies that arise from previously traumatized, chronically inflamed, or scarred skin. We report a case of squamous cell carcinoma arising in a foot wound 42 years after the time of injury. The historical background, epidemiology, pathophysiology, diagnosis, treatment, and prognosis of Marjolin's ulcer are reviewed. Diagnosis is best accomplished by punch biopsy or excision of suggestive lesions. Wide local excision is required and amputation may be necessary to achieve an adequate margin. Regional lymph node dissection should be done if regional nodes are palpable. Elective lymph node dissection is controversial but should be considered if the tumor is poorly differentiated. Lymph node metastases and high tumor grade indicate a poor prognosis. Clinicians should be diligent in the long-term surveillance of all significant scars or areas of chronic inflammation.