Objective: The aim of this study was to compare the variation in the size of the oropharyngeal space (OS) in the preoperative, immediate postoperative and post-operative 5 to 24 months according to the amount of mandibular setback. Material and method: Variation were evaluated on cephalometric radiographs taken few days before the surgery (Rx1), immediate postoperative (Rx2) and postoperative long time (5 to 24 months) (Rx3). The subjects were 20 patients (18 - 36 years) in whom dentofacial deformity class III was corrected by bilateral sagittal split ramus osteotomy setback. Surgery was done in two Oral and Maxillofacial specialized institutions, since 2003 to 2010. We examined the size of the oropharyngeal space at different times before and after mandibular setback surgery. Results: These shows no significant difference between the amount of mandibular setback and decrease the size of the oropharyngeal space. It was determined that the oropharyngeal space immediately after surgery increases and decreases over time as a result of soft and hard tissue adaptation. Conclusions: We conclude that there is a slight decreased in the anteroposterior dimension of oropharynx after mandibular setback surgery, however the variations is no statistically significant difference between the moments of evaluation (the amount of mandibular recoil and the decrease in OS).Objetivos: Comparar la variación de la dimensión del espacio orofaríngeo (EO) en el prequirúrgico, postquirúrgico inmediato y postquirúrgico de 5 a 24 meses después de la cirugía de retroceso mandibular (CRM). Materiales y métodos: Se evaluaron las radiografías cefalométricas prequirúrgicas, postquirúrgicas inmediatas y postquirúrgicas de 5 a 24 meses de 20 pacientes con CRM del Servicio de Cirugía Oral y Maxilofacial de dos instituciones. Se cuantificó la dimensión del EO en diferentes momentos. Resultados: No se encontraron diferencias de significación entre la cantidad de retroceso mandibular y la variación de la dimensión del EO. Conclusiones: Existe una leve disminución de la dimensión del EO después de la CRM. No son estadísticamente significantes entre los momentos de evaluación. No se encontró correlación entre el retroceso mandibular y la disminución del EO.