Far-infrared reflection spectra and results of dielectric measurements of SrTiO3 single crystal doped by neodymium are presented in the paper. Dielectric investigations were conducted at temperature range from 25 K to room temperature for the test frequency 1MHz. The numerical analysis of the far-infrared reflection spectra made using a fitting procedure based on factorized form of the dielectric function. The results for SrTiO3: Nd are compared with those for pure crystal. The lowest-frequency phonon mode is found to be strongly influenced by presence of neodymium ions in SrTiO3 single crystal.