ABSTRACT Powdery mildew is a fungal disease which causes a serious reduction in both root and sugar yields in sugar beet area in Al-Fayum.This study was carried out at El-Fayoum Governorate, (29°17ˋ N; 30°53ˋ E), Egypt, to study the effectof three growth regulators (gibberellic acid (GA₃), indole acetic acid (IAA) and naphthalene acetic acid (NAA)) at the levels of 0, 100, 200 and 300 ppm concentration on disease severity, growth, yield and quality of sugar beet plant during 2018/2019 and 2019/2020seasons.The results revealed thatthe application of GA₃ followed by NAA then IAA as growth regulators decreased disease severity% of powdery mildewand increased growth, yield and quality of sugar beet crop compared to control treatment. Increasing growth regulator concentrations from zero up to 100, 200 and 300 ppm decreaseddisease severity% and increased yield and quality traits of sugar beet crop in both seasons under study.