Introduction: Distraction osteogenesis is a surgical technique that allows bone lengthening through a biological process of bone formation between two vascularized bone surfaces, which have been surgically sectioned and gradually separated, in a controlled way. This procedure is performed in patients with craniofacial malformations, of acquired or congenital etiology. Objective Study the effects produced by two different rates of distraction in beagle dogs' mandibular condyles by using Cone Beam Computed Tomography. Methods: Ten beagle dogs were randomized in two groups: Control Group, composed by three dogs that weren't submitted to distraction, and Test Group formed by seven dogs that underwent to distraction. Each test animal was subjected to two distraction rates: 0.5mm, twice a day on the right hemimandible, every 12 hours and 1 mm, once a day on the left. At the end of the process of distraction all animals were euthanized. For the study of the dogs' condyles CBCT's, the authors resorted to MATLAB® to analyze the images. Results: The differences between the mean value for the two groups is not statistical meaningful (t(24)=1.369;p=0.184). Discussion The mean value is higher in the group submitted to the slowest distraction rate suggesting that bone consolidation improves inversely to the distraction rate. Moreover, the literature states that changes on the condylar structure appear at high daily distraction rates. At physiologic rates, these changes are reversible. Conclusion: Distraction osteogenesis may induce adaptive changes on mandibular condyles, which can be influenced by distraction daily rates. Keywords: Distraction osteogenesis, temporomandibular joint, mandibular condyles, CBCT