Recently, many environmental fluctuations affecting sorghum production such water shortage, increases in temperatures, soil salinization, drought, improper use of soil and hyper-fertilization. There were Many studies attempted to solve these problems. Thus, this study is conducted to investigate the effect of foliar spraying riboflavin at different concentration on growth traits, proline content in the plant, grain yield and yield components of three sorghum cultivars. Results revealed that Rabih cv. was significantly superior in most studied traits, such as plant height, leaf area, leaf area index, flag leaf area, leaves proline content and number of grains per head. This increment in the traits mentioned previously reflected positively on grain yield per unit area in both seasons as it produced 7.05 and 7.12 ton/ha, respectively. Foliar application of riboflavine improved most of vegetative growth traits including plant height and leaf area, while it reduced the proline content in plant which make it able to  avoid stress during its life time. This in turn increased the grain yield and its components. In both season, foliar application of riboflavin at the conc. of 300 mg l^-1 gave the highest grain yield amounted to 7.29 and 7.22 ton h^-1, respectively.  There were significant interaction between cultivars and riboflavin conc. in most traits. It can be concluded from this study that high grain yield can be obtained by sowing Rabih cv. and spraying with riboflavin at concentration of 300 mg L^-1