Calculations of energy levels of 1s²2s²2p⁵nl, 1s²2s2p⁶nl (n = 3–6, l = s, p, d, f) configurations of Ne-like ions with Z = 20-60 have been carried out with use of an MZ program. The energy matrix in this method (1/Z method or Z–expansion) is represented in the form of a Z-expansion, where Z is the nuclear charge. Relativistic effects are taken into account in the framework of the Breit operator. The contributions of radiative and high order relativistic effects are also considered. The results of the calculations are compared with theoretical and experimental data.