The structural, elastic and electronic properties of YAg-B2(CsCl) were investigated using the first-principles calculations. The en- ergy band structure and the density of states were studied in detail, including partial density of states (PDOS), in order to identify the character of each band. The structural parameters (lattice constant, bulk modulus, pressure derivative of bulk modulus) and elastic constants were also obtained. The results were consistent with the experimental data available in the literature, as well as other theoretical results. The structural, elastic and electronic properties of YAg-B2 (CsCl) were investigated using the first-principles calculations. The en- ergy band structure and the density of states were studied in detail, including partial density of states (PDOS), in order to identify the character of each band. The structural parameters (lattice constant, bulk modulus, pressure derivative of bulk modulus) and elastic constants were also obtained. The results were consistent with the experimental data available in the literature, as well as other theoretical results .