A possible anomaly in the temperature dependence of nonlinear dielectric susceptibility chi(nl) of relaxor ferroelectrics related with the freezing phase transition was investigated. First, based on the phenomenological approach, the anomaly in the chi(nl) was analyzed, including its shape, sign, and crystalline anisotropy. Second, the theoretical results were applied to the analysis of experimental data on nonlinear dielectric permittivity of single crystals of PbMg1/3Nb2/3O3 (PMN) relaxor. It was concluded that in contrast to earlier publications, there is no evidence for the anomaly in chi(nl)(T) of PMN related with the freezing transition. (C) 1999 American Institute of Physics.