Perchlorate concentrations in rice samples from many different provinces, and correlation with surface water contamination, were investigated in the Republic of Korea. Perchlorate levels in the 51 rice samples purchased from local markets ranged from below the detection limit to 1.79 ± 0.39 μg/kg with a mean level of 0.21 μg/kg and 7 samples collected from the Nakdong River watershed ranged from 0.38 ± 0.1 to 3.23 ± 0.47 μg/kg with a mean level of 0.9 μg/kg. The correlation coefficient between perchlorate levels in rice samples from the Nakdong river watershed and the levels in surface water was estimated to be approximately 0.904 in the 95% confidence interval. These results show that surface water contamination was highly related to the perchlorate pollution of rice in the Republic of Korea.