Understanding the relationship between ethnicity and free prostate specific antigen (fPSA) could identify the population that should be targeted for intervention and prevention program regarding prostate disease. In this study, we therefore examine the effects of aging and ethnicity on fPSA, measured in serum by chemiluminescent assay (CLIA) method of 351 men visiting Tribhuvan University Teaching Hospital (TUTH) for fPSA test from December to March. Medicinal records abstracts were used to obtain information regarding the ethnicity and age of the cases. Those cases whose age and surname could not be obtained were excluded in our study. The subjects were stratified in four ethnic groups viz; Indo-Nepalese, Tibeto-Nepalese, Indigenous and Other based on the origin. The relationship between age and fPSA level was analysed using bivariate coorelation. The age and the fPSA level of the cases were expressed in Mean ± SEM. The association among different age-group and ethnicity with fPSA were analysed using one way ANOVA. The mean fPSA and mean age of the subjects were 1.74 ± 0.22 and 66.84 ± 0.64 respectively. fPSA level was fairly correlated with the age (r=0.146, p=<0.01). The mean fPSA level (ng/ml) among the four age category (<45, 45-60, 60-75 and >75) were 0.49 ± 0.13, 0.69 ± 0.10, 1.94 ± 0.04 and 2.33 ±0.43 respectively. The difference in mean fPSA level among four different age-groups was statistically significant (p=0.031). Analysis showed no correlation between the fPSA level and the ethnicity. These data suggest that the fPSA level is associated with the age.