Chronic venous leg ulcers (VLU), especially long-lasting non-healing ulcers, are among the risk factors for squamous cell carcinoma (SCC). Malignant transformation of a VLU is a rare finding and the relative risk of carcinomatous transformation is quite low (about 5.8). SCC arising in the context of a VLU has a particularly aggressive behavior. A 76-year-old male patient with no relevant medical familial history, with chronic venous insufficiency CEAP C6 for 10 years [recurrent leg ulcers with favorable outcome (healing) after specific local and systemic treatment], showing for about three years one ulcerated lesion located on the anterior upper third of the right calf non-responsive to specific treatment, which subsequently increased their size and merged. Biopsy sample was taken. Histopathology showed epidermal acanthosis, papillomatosis, intense parakeratosis, pseudoepitheliomatous hyperplasia, dysplasia and moderately differentiated squamous cell carcinoma with areas of acantholysis. Immunohistochemistry (Ki67, EMA, cytokeratin 34βE12 and p63) was performed and all types of immunostaining were moderately to intense positive. Above-knee leg amputation and specific oncologic treatment were proposed as possible curative solutions but the patient refused. Ten months after diagnosis and discharge form the Department of Dermatology, the patient died. Patients with chronic venous leg ulcers and clinically suspicious lesions should be evaluated for malignant transformation of the venous lesion. When diagnosed, malignancy complicating a chronic venous leg ulcer requires a resolute treatment as it may be fatal.