Tooth morphology is important to achieve aesthetic, functional and optimal occlusion of teeth. Collum angle plays an important role for the attainment of these obvious objectives of the orthodontic treatment . The angulation of the root to the crown, particularly of the single rooted anterior teeth is known as Collum angle. In other words angle formed by the intersection of the long axis of the crown and root and it is measured using the lateral cephalogram. This angle may limits the tooth movements of incisors specially when it is torque lingually because of the lingual cortical very near to the roots of central incisors. The extent of recession is related to the bending angle. Gingival recession due to improper movement of tooth during orthodontic treatment may lead to cosmetic defects. Therefore, understanding the crown-root angle in patients with different types of malocclusion is a critical issue. The present study was done to assess the collum angle in population of western Nepal. Keywords: Collum angle, root, angle, cephalogram