The half-metallic calculations of MnZrX (X = In, Tl, C, Si, Ge, Sn, Pb, N, P, As, Sb, O, S, Se Te) half-Heusler compounds were investigated using WIEN2k code. In all compounds, the ferromagnetic (FM) phases were the most stable states energetically. The spin-up electrons of all half-Heusler compounds have semiconducting nature with energy gaps while spin-down electrons have metallic behavior. According to calculated C-ij elastic constants, MnZrIn, MnZrTl, MnZrSi, MnZrGe, MnZrSn, MnZrPb, MnZrP, MnZrAs, MnZrSb, MnZrS, MnZrTe halfHeusler compounds are elastically stable except MnZrC, MnZrN and MnZrO compounds. Additionally, MnZr(In, Tl, C, Si, Ge, N, P, As, Sb, S and Se) compounds are ductile and MnZr(Sn, Pb, O and Te) compounds are brittle materials. Finally, MnZr(In, Tl), MnZr(C, Si, Ge, Sn, Pb, O), MnZr(N, P, As, Sb), MnZr(S, Se, Te) half-Heusler compounds were obtained true half-metallic ferromagnets (HMF) within 4.00, 3.00, 2.00 and 1.00 mu(B)/f.u. respectively.