Automatic facial expression recognition has gained much attention during the last decade because of its potential application in areas such as more engaging humancomputer interfaces. This paper explores the automatic recognition of facial expressions using 3D range images. The paper outlines the development of an algorithm designed to distinguish between neutral and smiling faces, and summarizes its experimental verification with a database containing 30 subjects who posed for both (neutral and smiling) expressions. The results of the experiments are very encouraging.