Present study was conducted under sprinkler irrigation system at private farm in Al-Salehya Al-gadida city, Al-Sharkia Governorate, Egypt. Two field experiments were conducted during two successive growing seasons 2016/2017 and 2017/2018 to study the effect of irrigation intervals (3, 5 and 7 days) and soil application of humic acid at rates of [0 kg (Control), 2.5 Kg and 5 Kg/Fed] in form of potassium humate on yield and quality of sugar beet (Beta vulgaris L.) variety Nancy (multigerm). A split plot design with three replications was used. Irrigation intervals allocated in the main plots, while the potassium humate levels were arranged in sub plots. Obtained results showed that decreasing irrigation intervals from 7 to 3 days significantly increased diameter and root fresh weight/plant, TSS % and root, top and sugar yields/fed in both seasons. Increasing humic acid rates from zero up to 5 kg/fed increased significantly root length, root diameter, root fresh weight/plant as well as root, top and sugar yields/fed and slightly juice quality in the two growing seasons. Moreover, the highest values of TSS % and sucrose % were recorded with humic acid treatments at 2.5 kg or 5 kg/fed in both seasons. Effect of interaction between irrigation intervals and humic acid applications didn't reach the 0.5% level of significance concerning root length, root yield/fed and sugar yield/fed in the two seasons, while the effect of interaction on TSS %, sucrose %, purity % and  top yield/fed didn't reach the level of significance in the first season only.