Recently, two glufosinate-tolerant rice varieties, Iksan483 and Milyang204, were developed in Korea generated by adding bar gene to genomes of the conventional rice varieties. Comparative assessment of nutritional composition was conducted with genetically modified rice grains and its conventional counterparts for substantial equivalence. Nutrients including proximates, fatty acids, amino acids, minerals, vitamins, and antinutrients were investigated using several statistical comparisons. The results showed that, except for small differences in a few fatty acids, minerals, and trypsin inhibitor, there was no significant difference between genetically modified rice and conventional counterpart variety with respect to their nutrient composition. Most of measured levels of nutrients were in good compliance with the literature ranges, showing substantial equivalency. The results of principle component analysis demonstrated that the environment affects the nutritional composition and that all differences between the genetically modified and conventional rice varieties are within the range as the differences observed among conventional varieties grown in different years. Therefore, the insertion of bar gene did not change the nutritional composition of genetically modified rice grains.