Infundibular keratinizing acanthoma (IKA) is a benign cutaneous tumor in dog originated from the hair follicle. The present study describes IKA in a 4 year old, male terrier dog. Macroscopically, a cutaneous dome-shaped nodule, 2-3 cm in diameter, with firm consistency, irregular surface and a central pore was located on the back for several months. The histopathological examination revealed a large cyst filled with concentric lamellar keratin that extended into the dermis and hypodermis. The wall of the cyst was lined by the stratified squamous keratinizing epithelium. Cords of epithelial cells had one or two cells thickness expanded outward from the peripheral zone of the cyst wall. The epithelial cells were well-differentiated. Mitosis was rare and there was not polymorphism.