Background: Mandibular coronoidal process hyperplasia (MCPH) is defined as enlargement of normal bone which is characterized by restriction in mouth opening. The term and measurement technique of hyperplasia were not determined clearly. The aim of study is to evaluate dimensions of condyle and coronoid, to determine the ratio between coronoid and condyle in the cone beam computed tomography (CBCT) images. Methods: 18 years and older 154 patients who had CBCT images for different reasons were evaluated retrospectively. A horizontal line was drawn passing at deepest point of sigmoid notch and height measurements were made from the top of coronoid and condyle on sagittal images. Distance between top of coronoid and the bottom point of zygomatic arch was measured on coronal images. The ratio between the coronoid and condyle was determined. The data were statistically evaluated by descriptive statistics and t test. Results: MCPH was detected six of 154 patients and these patients were excluded from the study and 148 patients (81 females, 67 males, mean age ± Sd; 37.66 ± 14.32 years) were included in the study. The mean height of right condyle was 16.70 ± 0.22 mm, mean height of the left condyle was 16.99 ± 0.22 mm, the mean height of right coronoid was 11.41 ± 0.23 mm, the mean height of left coronoid was 11.91 ± 0.24 mm. Averages height of the condyle and coronoid were higher in males than females (p=0.00). The average ratio between coronoid process and condyle was 0.70 ± 0.01 on the right side and 0.72 ± 0.01 on the left side. The ratio between the coronoid process and the condyle was greater than 1, bilateral in 18 patients and unilateral in 5 patients. Conclusion: Averages height of the condyle and coronoid were higher in males than females. In the literature, there is not enough information about the average length of the coronoid and a clear method for the diagnosis of MCPH. There is a need for studies using three-dimensional assessment, using objective measurement methods in various and larger populations.