The program processing γ-spectra named “GAMMAPEAKS”, was elaborated. This program can approximate peaks in γ-spectra with different Gaussian-like functions. The common Gaussian, the variable variance Gaussian and the sectionally defined Gaussian-like function were used as approximative functions. The contrastive analysis of quality of peaks approximating using no more than three approximative functions for one extremum in γ-spectra was performed. The quantitative and qualitative data determining the precision of approximating of γ-spectra peaks by different Gaussian-like functions are shown.