This study was conducted during two successive seasons of 2018 and 2019 on Balady Mandarin trees, 20 years old budded on sour orange rootstock and planted at 5×5m apart. Grown at the productive farm located at Shandawel Island, Sohag governorate. This experiment aimed to study the effect of active dry yeast, ascorbic acid, vitamin B complex and their combination on yield components, alternate bearing and fruit quality of Balady Mandarin cultivar grown under Sohage conditions. The obtained results showed that using of active dry yeast at 10g/l (as soil application) as single application or in combination with ascorbic acid and vitamin B complex at 1g/l from each (foliar application) caused a pronounced increasing of fruit numbers, fruit weight (g) and yield (kg). The later also improved fruit quality in terms of TSS%, TSS/acid ratio as well as total sugars, vitamin C content and reducing total acidity of Balady Mandarin fruits. According to results of the current study it could be concluded that using active dry yeast at 10g/l (as soil application) as single treatment or in combination with spraying ascorbic acid (1g/l) plus vitamin B complex (1g/l) three times on the first week of May, July and September led to improve both yield and fruit quality of Balady Mandarin Cultivar under Sohage environmental conditions. [ABSTRACT FROM AUTHOR]