The current research was conducted at El-Mattana Agricultural Research Station (latitude: 25.25°N and longitude: 32.31°E). Luxor Governorate, Egypt during 2020/2021 and 2021/2022 (two plant cane crops). This research aimed to assess the optimum age at harvest (11, 12, 13 and 14 months old) for six promising sugarcane varieties (G.2003-47, G.2004-27, G.2005-47, G.2000-5, G.2009-11and G.2015-37) compared with the commercial variety (G.T. 54-9). The examined treatments were distributed in a split-plot design with three replications. Sugarcane varieties were assigned to the main plots while the ages at harvest were distributed in the sub-plots. The results indicated that sugarcane varieties significantly differed in all studied traits. G.2004-27 variety recorded the highest millable cane length and cane yield in both seasons, while variety G.2005-47 gave the highest values of millable cane diameter, weight and sugar yield. However, the differences in millable cane weight between the sugarcane variety G.2005-47 and variety G.2004-27 were insignificant, in the second season only. Sugar cane variety G.2003-47 recorded the highest sucrose, purity and sugar recovery in both seasons. Also, variety G.2000-5 gave the highest values of brix% in both seasons. Harvesting at 14 months old recorded the highest mean values of millable cane length, diameter, weight, brix and cane yield in both seasons, as well as sugar yield in the second season. The highest mean values of sucrose, purity, and sugar recovery in both seasons, as well as sugar yield in the first season, were recorded at 13 months old. Under this investigation, the maximum cane and sugar yield was obtained by G.2004-27 and G.2005-47 varieties when they were harvested at 14 and 13 months old, respectively.