The authors report a case of anomalous implantation of the base of the appendix, observed in a 8-yaer-old boy, arising from the anterior wall of ascending colon at 15 cm from the ileo-cecal valve. After a brief review of the most frequent congenital anomalies of the appendix and the few cases of anomalous implantation described in international literature, the authors emphasize the importance of an accurate exploration and mobilization of the ascending colon to reduce the risk of diagnostic and therapeutic mistakes, also related to the small incision of McBurney, usually made for the routinary laparotomic appendectomy.