Positions, angulation and mesiodistal dimension of lower incisors are important in esthetics, occlusion and post-treatment stability of lower arch. When lower incisor is congenitally missing, problems such as increased overjet and overbite, closing in of adjacent teeth and size/space discrepancies may occur. When creating treatment plans, incisor position and angulation, lip support, anteroposterior skeletal relationship canine-molar relationship; overjet, overbite, remaining growth potential, crowding and anterior tooth ratio have to be considered For an accurate analysis of incisal size discrepancy, diagnostic model set-up may be helpful. The two patients in this presentation both had two lower incisor missing, but the degree of crowding, skeletal relationship, lip support, molar relationship are different, and therefore treatment plan was different as well. Long term follow-up may be necessary for stability and retention.