Introduction: The most important function of Speech is communication and any disorder in Speech undoubtedly affects communication with other people. Speech disorders have a significant effect on social development of human beings. This study was undertaken to evaluate the relative incidence of Speech disorders in sagittal dento-alveolar disorders.Materials and methods: In this descriptive analytical study 95 patients referring to the Orthodontics Department of Khorasgan Dental School in spring 2008, who met the inclusion criteria (subjects with one of the Angle’s 3 classes of malocclusion based on preliminary evaluations, no history of orthodontic treatment and with no other problems such as mental retardation or cleft palate) were randomly selected and underwent dentofacial examinations. A Speech therapist evaluated the subjects’ Speech disorders via phonetic test and colloquial Speech. Data were analyzed with chi-squared test using SPSS 16 (a=0.05).Results: Chi-squared test did not reveal any significant relationship between Speech disorders and Angle’s malocclusion (p value=0.07). The group with dentofacial disorder and the group without it were matched in relation to sex (p value=0.092) and age (p value=0.543). In addition, of all the consonants the most common disorder was related to abrasive consonants and the Speech disorders were not evenly distributed among all the consonants (p value<0.001).Conclusion: The results showed no significant relationship between Speech disorders Angle’s malocclusion. The most frequent disorder was related to abrasive consonants.