A 58-year-old Japanese man was admitted complaining of abdominal pain. An abdominal computed tomography examination demonstrated a tumor in the head of the pancreas and multiple calcifications. A laparotomy was performed and the tumor was removed by Whipple's operation. Histologically, the neoplasm that invaded the duodenal wall and the papilla of Vater was composed of nests of malignant squamous cells with intercellular bridges and showed the formation of keratinized pearls with a small area of concurrently neoplastic glandular and squamous elements. On the basis of these features, the diagnosis of adenosquamous carcinoma of the pancreas was made. The patient died 18 months after the operation. The neoplastic behavior of this rare primary pancreatic carcinoma is similar to that of duct cell carcinoma as well as pure squamous cell carcinoma of the pancreas. As the pancreas can be the target of metastases of squamous carcinomas from other organs it is wise to be aware of this rare entity.