Squamoid eccrine ductal carcinoma (SEDC) is a rarely reported malignant skin tumor. It is characterized by showing both atypical squamous and ductal differentiation. SEDC occurs on sun-exposed area and appears as gradually developed nodular or ulcerative lesions. We describe a case of SEDC on the left ear helix of an 80-year-old male patient. After receiving a punch biopsy for diagnosis, the patient underwent a wide excision to remove the tumor. Histopathology results revealed ulcerative, infiltrative lesions extending from the epidermis to the upper dermis with atypical squamous cell proliferation. Tubular and ductal structures with hyperchromatic nuclei were observed in the deeper layer of the dermis. Immunohistochemistry showed positive staining for CK5/6, CK7, Epithelial membrane antigen, P53, and P63. Carcinoembryonic antigen, S-100, gross cystic disease fluid protein 15 and periodic acid-Schiff showed negative staining. The biphasic histopathology features and immunohistochemistry findings help differentiating SEDC from squamous cell carcinoma and other eccrine origin malignant tumors. Clinically, SEDC frequently appears on sun-exposed body areas, especially on the head and neck. It also shows local recurrence despite complete resection. These characteristic features demand cautious attention for diagnosis and treatment of SEDC.