Considering the natural abundance of the constituting elements and first-order phase transition (FOPT), LaFe_13-xSi_x-derived compounds have been extensively studied for magnetocaloric effect, a phenomenon that causes the cooling or heating of material when placed in an external magnetic field 1. They are, however, extremely brittle and mechanically friable, showing rather low thermal conductivities and measurable irreversibility, which thus far could not be eliminated completely. Recently, Pathak et al. 2 reported the first-time discovery of a two-phase, naturally formed at the LaFe₂Si stoichiometry rather than LaFe_13-xSi_x compound. LaFe₂Si exhibits strongly responsive behaviors without the degradation in properties that can be exploited in weak magnetic fields. However, the phase transition happens rather at low temperatures and the saturation moment is low. We are working on this material to further enhance the phase transition temperature and also to improve the magnetic and mechanical properties of the alloy. In this presentation, we will present the synthesis and characterization of LaFe_2-yCo_ySi. We prepared LaFe_2-yCo_ySi by making the first pre-alloy of FeCoSi and then added Co and melted several times. The alloys were further homogenized by the vacuum suction casting technique, which prepared a 4 to 5 cm long rod with a 6mm diameter of sample. The ferromagnetic to paramagnetic transition temperature increases from 199K for x = 0 to 273K for x = 0.3 and the full width at the half-maximum value of magnetic entropy changes increases significantly with Co doping. We discuss the phase transition, electrical transport, magnetic and magnetocaloric properties of LaFe_2-yCo_ySi compounds.