The structural, magnetic and magnetocaloric properties of CoMn_1-xCr_xGe (x=0.05-0.125) have been investigated by using electron microscopy, x-ray diffraction, calorimetric and magnetic measurements. In this study, our aim is to justify the magnetocaloric effect by tuning the structural and magnetic transition temperature with Cr doping on CoMnGe pure system. The substitution of Cr for Mn leads to a decrease of both structural and magnetic transition temperatures. However, structural and magnetic transition temperatures do not close to each other. From magnetization measurement, we calculate that isothermal entropy change associated with magnetic transition can be as high as 3.82 J kg⁻¹K⁻¹ at 302 K in a field of 7 T. Meanwhile, structural phase transition contribution to isothermal entropy change is calculated as 5.85 J kg⁻¹K⁻¹ at 322 K for 7 T.