Cranial parameters and cephalic indices are used to evaluate the racial and gender differences. The aim of this study was to assess the cephalic indices, to classify the type of cranium and to determine the relationship between the horizontal cephalic index and cranial parameters among Iranian medical students. This study was done on 200 medical students (100 males and 100 females) with an age range of 18-30-year-old. Head length, head breadth, and auricular height were measured by using a standard spreading caliper. Then cephalic indices were calculated for the classification of cranial type. The linear regression was used for examining the relationship between the horizontal cephalic index and head length, head breadth and auricular height. The results of this study showed that the mean of the horizontal, vertical, and transverse cephalic index in total students were 83.51±6.85, 85.58±5.85 and 102.77±6.35 cm, respectively. According to this result, the predominant head shapes in total students were brachycephalic, hypsicephalic and acrocephalic types. In this study, there was a strongly negative correlation between horizontal cephalic index with head length (r=-0.744, P=0.000), moderate positive correlation between horizontal cephalic index with head breadth (r=0.512, P=0.000) and weakly negative correlation between horizontal cephalic index with auricular height (r=-0.205, P=0.004). The data of the present study can be beneficial in craniofacial reconstruction, clinical diagnosis, and forensic applications
