Probiotic whey-based custard apple beverages (P.C.A.B.) were prepared with different combinations of whey and custard apple pulp juice , PJ (75:25, 50:50 and 25:75 , weight :weight ) and inoculated with1% probiotic bacteria Lactobacillus casei. Beverages were evaluated for physic-chemical, microbiological and sensory properties, during cold storage. Total solids and the apparent viscosity were increased in (P.C.A.B.) treatments as the level of P.J. increased, whereas values of titratable acidity (T.A) were decreased, compared to control treatment. The pH values of all treatments behaved reverse trend to T.A, through the storage period.Total antioxidant compounds, vitamins A & C and minerals were found higher in fresh beverage contained 25% P.J. than control one. The rate of increase (%) in the antioxidants, vitamins A & C were 9.09, 135.30, and 173.30, respectively. Minerals were increased also in (P.C.A.B.) but in a variable ratios. Counts of probiotic lactobacilli were gradually decreased as the storage period increased and as the level of P.J. increased. The  probiotic strain  was still viable, in all treatments, with counts more than 10⁶cfu/ml , while coliform group & spore-forming bacteria were absent in all treatments, during storage. Control treatment was less acceptable, at the 21 days  of storage as a result of growing yeast & molds with counts reached to 30×10² cfu/ml.The beverage prepared from 75% whey : 25% P.J. was found superior organolepticaly than the other ones, along the storage period. It has clean acid flavor and long keeping quality up to 40 days of  storage .