There are evidences that occlusal splint therapy is critical to diagnose hidden skeleto-occlusal disharmonies in malocclusion patients and capable of enhancing stability after orthodontic treatment. In addition, evidences have implicated occlusal splint therapy in condylar positional changes during TMJ disorder treatment. In view of these evidences, this study was performed to investigate the effect of occlusal splint therapy on condylar positional changes in malocclusion patients and the possible clinical application of the occlusal splint as an additional orthodontic tool. For this study, 8 Angle´s Class I malocclusion patients, who had centric occlusion-centric relation discrepancy within 1.0 mm and had no clinical symptoms of TMJ disorder, were selected as control group. And 22 malocclusion patients who had centric occlusion-centric relation discrepancy over 1.0mm were selected and subdivided as Class I Malocclusion group, Class II div. 1 malocclusion group, Class II div. 2 malocclusion group, Open bite group, and Mandibular asymmetry group. For each subject the occlusal splint with mutually protected type of occlusal scheme was applied for 3 months. Condylar positions in centric relation and centric occlusion were measured using Panadent articulators and Panadent condylar position indicator (CPI) before and after occlusal splint therapy. On the basis of this study, the following conclusions might be drawn: 1. In control group, Class II div. 2 malocclusion group, and mandibular assymetry group, there were no significant differences in condylar positions before and after occlusal splint therapy. 2. In Class I malocclusion group, condyles were moved 0.27 ± 0.45 mm forward (p<0.05) and 0.98 ± 0.25mm upward (p<0.01) after occlusal splint therapy. 3. In Class I malocclusion group, condyles were moved 0.24 ± 0.21mm backward (p<0.05) and 1.01 ± 0.33mm upward (p<0.01) after occlusal splint therapy. 4. In open bite group, condyles were moved 1.24 ± 0.30 mm upward (p<0.01) after occlusal splint therapy. 5. In both control and experimental groups, there were no significant differences in lateral condylar positions before and after occlusal splint therapy.