The electronic structure, magnetic and elastic properties of Ir2MnSi full-Heusler compound is studied within the framework of Density Functional Theory (DFT). The ferromagnetic (FM) and non-magnetic (NM) states are compared in Cu2MnAl and Hg2CuTi prototype structures. The ferromagnetic state in Cu2MnAl structure has been found energetically more stable than nonmagnetic state in these two types of structures. Due to this stability, all calculations are carried out for FM-state. The spin-polarized calculations show that the spin-up electrons of Ir2MnSi compound have metallic nature, but the spin-down electrons have semiconducting behavior with 0.55 eV energy gap around the Fermi level. The calculated Cauchy pressure and Poisson's ratio indicated that Ir2MnSi compound is a ductile material. Ir2MnSi compound is a half-metallic ferromagnet (HMF) and it has 5 mu(B) magnetic moment. This study will theoretically lead to experimental works in the spintronic field and its applications.