Aplasia or hypoplasia of the uncinate process is associated with maxillary sinus aplasia or hypoplasia. It is of particular clinical importance to recognize the presence of normal or abnormal uncinate processes in patients who will undergo surgical procedures for paranasal sinus diseases. In this report, we present a case of aplasia of bilateral uncinate processes. discuss the variations of uncinate processes, and review related literature. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.