Marjolin ulcers are malignant tumors arising in chronic wounds. Strictly defined, they include carcinomas that transform from the chronic open wounds of pressure sores or burn scars. They behave aggressively and have a propensity for local recurrence and lymph node metastases. A retrospective study was done at a single institution identifying six individuals who had chronic wound ulcers that underwent malignant transformation into a carcinoma. Sinus tract degeneration in osteomyelitis was not included. The average latency time between ulcer formation and documentation of a malignancy was 30 years. All wounds were about the pelvis or flank. Major oncologic surgical procedures were done in an attempt to eradicate the cancer. High-grade tumors had positive lymph node metastases, portending a grave prognosis. All four individuals with nodal metastases eventually died of systemic disease. Early recognition and proper staging offers the best chance for cure.