Validation procedure for method of monitoring the biological activity of reсombinant human interleukin-7 has been developed and conducted according to the requirements of national and international recommendations. This method is based on the ability of recombinant human interleukin-7 to induce proliferation of T lymphocytes. It has been shown that to control the biological activity of recombinant human interleukin-7 peripheral blood mononuclear cells (PBMCs) derived from blood or cell lines can be used. Validation characteristics that should be determined depend on the method, type of product or object test/measurement and biological test systems used in research. The validation procedure for the method of control of biological activity of recombinant human interleukin-7 in peripheral blood mononuclear cells showed satisfactory results on all parameters tested such as specificity, accuracy, precision and linearity.