The research aimed to determine the rice grain quality of some promising lines from the advanced breeding generation of swamp rice and upland rice. The research material was 43 rice grain samples from the multilocation test sites of swamp rice (16 rice lines, 3 check varieties) and upland rice (20 rice lines, 4 check varieties) harvested in 2018. All rough rice samples were analyzed for the rough rice physical quality, milled rice physical quality, milling quality, physicochemical quality, and organoleptic quality (scoring test and hedonic test). The results showed that in general, the promising lines of swamp rice had higher values of unpolished rice yield, polished rice yield, head rice percentage, and protein content than those of upland rice. In addition, the promising lines of swamp rice had lower empty rough rice and immature+chalky grain than those of upland rice lines. Among the promising lines of swamp rice, B13926E-KA-43, B13931E-KA-33, and BP30400F-KA-5 had the highest head rice percentage, unpolished rice yield, and polished rice yield, whereas, among the promising lines of upland rice, B15392D-KR-12, B15511D-KR-20, and B15514D-KR-5 had the highest head rice percentage, unpolished rice yield, and polished rice yield.