Background: Objectives: the aim of this study was to evaluate the changes occurred in posterior cleft width in unilateral cleft lip and palate patients after utilizing acrylic nasoalveolar molding device Materials and methods: ten patients with unilateral cleft lip and palate were treated with acrylic nasoalveolar molding device. Maxillary dental models were scanned at two points of time S0 (before treatment) S1 (after finishing the treatment) these models were used to asses changes in posterior cleft width using software.