Red rice is one of the important functional food sources because its anthocyanin content is very beneficial for human health. One of the processes to produce new superior varieties of rice is by cross-breeding. The aim of this study was to determine the agronomic performance of the promising lines of red rice resulted from crossing of IPB3S variety with the promising line of red rice compared with the parents and comparison genotypes in the medium elevation lands. The experiment was carried out in June - September 2022 in medium lowland rice fields (375 m asl) in Central Lombok district, NTB, Indonesia, which was designed using a Randomized Block Design (RCBD) consisting of 14 treatments, namely 9 ideal type red rice lines resulted from Pedigree F5 selection, 1 promising line of red rice from crosses between Kenya and Angka, two parents (the promising line of paddy red rice “GH F2BC4P19-36”, and IPB3S variety), and two control varieties (Situ Patenggang and Inpago Unram 1), repeated 3 times. Observation variables included plant height, days to harvest, number of productive and non-productive tillers, length of panicles, number of filled and unfilled grains per panicle, weight of 100 grains, grain weight per clump and yield potential (tons/ha). The results showed that the red rice line G6 (F5 IPB3S/F2BC4P19-63// Fat/F2BC4P19-63-PD3/17) showed higher grain yield potential (4.79 t/ha) compared to the two parents, namely IPB3S (3.34 t /ha), GH parent (3.27 t/ha), Situ Patenggang (3.92 t/ha) and Inpago Unram 1 (3.35 t/ha). Plant height, number of productive and non-productive tillers per clump, panicle length, numbers of filled and unfilled grains per panicle, grain weight per clump and potential grain yield per hectare were significantly different between genotypes while days to harvest and 100-grain weight were not significantly different.