Electrochemiluminescent (ECL) method was used for cytokine detection with TAG label (ruthenium(II) tris-bipyridine chelate N-hydroxysuccinimide ester). A quantitative ECL detection of IL-4 and IFN-gamma in physiological fluids and cell culture media is described. The results evidence that ECL is compatible to commercial kits or even more effective. The advantages of ECL are simple procedure, no need in washings, small volume of the assay, wide range of cytokine concentrations, high sensitivity, and good reproducibility. The method can be used in research and clinical laboratories.