This study aimed to investigate the effect of dietary probiotic supplementation during rearing period on subsequent laying performance and physiological response of Sinai hens during laying period.  A total number of 360 Sinai chicks, one old day were used in the current trail. Chicks were divided into 4 equal groups each of 3 replicates. Experimental groups were as follows, 1^st group served as a control and fed the basal experimental diets, while, the 2^nd, 3^rd and 4^th groups were fed the basal diets supplemented with 0.3, 0.4 and 0.5 g probiotic / kg, respectively from hatch up to 20 wks of age. The commercial probiotic used was Saltose Ex which is a thermo stable probiotic where it contains lactic acid bacteria (Lactobacillus lactis) 2.5x 108 CFU, Bacillus subtilis 1.8x 109 CFU/g product.  Results indicated that feed consumption and feed conversion ratio were significantly (P≤0.05) between the experimental treatments during rearing period (1-20 weeks of age). The relative weights of carcass, liver, giblets and length of jejunum and illeum at end of experimental period were significantly affected due to dietary treatment. The feeding on diet supplemented with 0.3 g probiotic /kg diet during rearing period resulted in a lower intestinal microbial count of both TCC and CC than control diet. Laying rate%, egg weight and egg mass were significantly increased due to dietary treatment as compared to the control. All dietary probiotic levels significantly reduced feed consumption within the whole laying period except the birds fed 0.4 g probiotic /kg diet as a subsequent effect during the laying period. Fertility % was significantly increased in eggs produced from birds fed diet supplemented with 0.4 and 0.5 g probiotic/kg diet, while, hatchability % was improved by feeding on diet with 0.3g probiotic/kg diet during rearing period as compared to the control diet. Therefore, these results indicate that dietary probiotic supplementation from 0.3 to 0.5 g/kg diet during rearing period could be used to improve welfare status to Sinai chicks and subsequent productive traits during laying period.