This 6-weeks study was conducted to investigate the efficiency of Bacillus amyloliquefaciens as probiotic in laying hens. A total of 180 ISA brown laying hens (28-weeks-old) were randomly allocated into 90 cages (two hens per cage), and then assigned to three dietary treatments with 10 replicates per treatment (each replicate with three adjacent cages): (i) CON, basal diet (antibiotic-free); (ii) P1, CON þ1.0 Â 10 7 cfu/kg probiotic; (iii) P2, CON þ2.0 Â 10 7 cfu/kg probiotic. The probiotic was a commercial product. The Hen Day production was daily recorded. The egg quality parameters were measured by using egg multi-tester. The caecal contents and fresh excreta were collected for measuring the caecal microflora and excreta gas emission, respectively. All data were analysed using the GLM procedure of SAS. Differences among treatment means were determined using the Tukey's range test. During 4-6 weeks, hens fed P1 and P2 diets had a greater (p < .05) egg production than those fed CON diets. Additionally, birds in P2 treatments had higher (p < .05) eggshell strength and eggshell thickness than those in CON treatment at 3 and 6 weeks. The caecal Lactobacillus numbers were increased (p < .05) while the caecal Escherichia coli and Salmonella concentrations and the excreta NH 3 emission were decreased (p < .05) in the P1 and P2 groups. In conclusion, dietary B. amyloliquefaciens supplementation had positive effects on productive performance in laying hens.