The present study throw lights on the comparing influence of dietary supplementation of live dried yeast Saccharomyces cerevisiae and chitozan on digestion coefficient and molecular biology of some cellulolytic bacteria in male Balady goats. A total number of 12 castrated adult male Balady goats aged one-year-old were allocated into three groups (4 males each). Concentrates were offered at rate of 3% of body weight. Experimental groups were control group fed on basal diet con‌sists of concentrate mixture without any feed additives; Saccharomyces cerevisiae group fed on basal diet with feed additive of S. cerevisiae at rate of 0.3% (3 Kg/ ton concentrate); chitosan group fed on basal diet with feed additive of chitosan at rate of 0.2% (2 kg/ ton concentrate). The obtained results revealed significant increases (p< 0.05) in nutrient digestibility of dry matter (DM), crude protein (CP), ether extract (EE), crude fiber (CF), nitrogen free extract (NFE), and Ash and a significant (P≤0.05) up regulation of genes expression level in S. cerevisiae and chitosan groups when compared with the control except in EE showed non significant increase in chitosan group comparing with the control group. Thus, it is recommended to use S. cerevisiae to improve feed efficiency of diet, growth and multiplication of ruminal microbes.