Sixty-five from a total of 160 medical students were administered the California Psychological Inventory (CPI) to identify which of all 18 scales can be used as a predictor for academic performance. The entrance examination scores of six subjects were also combined with the CPI variables for the purpose of the study. Students' performances were determined by Grade Point Average (GPA) collected between 1993-1997 (year 1 to year 5). Data was analyzed by descriptive and stepwise method of multiple linear regression analysis. The results showed that mathematics, biology and English language were positively correlated with all year GPAs-r2 value was 10-18 per cent. Scales of "dominance", "flexibility" and "socialization" were positively correlated to the GPA, while "sociability" and "sense of well-being" were negatively correlated. R2 value was increased to 16-59 per cent as prediction of GPA when the CPI variables were combined with scores of entrance examination. A comparison of this finding with other studies was conducted.