The mutational events that take place in mammalian somatic cells influenced with different endogenous and exogenous factors are presented in this review. The nonchromosomal method of research allows taking into account the complex cell characteristics without time-consuming analysis of the chromosomes as such. As a result, the information can be obtained about the mitotic (phases of mitosis, the number of nuclei per cell, micronuclei, pathology of mitosis) and vital (mitotic index, apoptosis) cell statuses, as well as about the state of chromosomal integrity (the presence of nucleoplasmic bridges, nucleus protrusions, chromosome fragmentation, micronuclei). Depending on the material studied (erythrocytes and lymphocytes of peripheral blood, buccal cells, permanent cell lines etc.), a complex of cytogenetic characteristics can be selected for each case which is the most informative for determination of the mutational spectra in mammalian somatic cells.