Abstract: The study was conducted to investigate the effect of dietary inclusion of cassava yeast as a probiotic source on laying hens performance and egg quality. Two hundred and sixteen Roman breed laying hens (26 week of age), were used. The laying hens were randomly allocated to 24 pens containing 9 laying hens each with 6 replicates and assigned to receive one of 4 dietary treatments (1. Control, 2. S. cerevisae 1x106 organisms/kg, 3. S. cerevisiae 1x107 organisms/kg, 4. S. cerevisiae 1x108 organisms/kg) in a completely randomized design. The results showed that feed intake, feed conversion efficiency, albumin weight, yolk weight and haugh unit were not significantly different among treatments (p>0.05). Significant differences were observed in egg production, egg weigh and shell thickness. Cassava yeast as probiotic source had positive effect on egg weigh and shell thickness, but has negative effect on egg production. The results of the present experiment showed that dietary inclusion of cassava yeast as a probiotic to laying hens seems to have minimal influence on laying hens performance.