Oxidation ofunsymmetrical dimethylhydrazine(UDMH) during a wa-ter treatment has several disadvantages including formation of stable toxic byproducts. Effectiveness of treatment methods in relation to UDMHtrans-formation products is currently poorly studied. This work considers the effectiveness of chemical oxidants in respect to main metabolites ofUDMH – 1-formyl-2,2-dimethylhydrazine (FDMH), dimethylaminoacetontrile (DMAAN), N-nitrosodimethylamine (NDMA) and 1-methyl-1H-1,2,4-triazole (MTA). Experiments on chemical oxidationby Fenton’s reagent, potassium permanganate and sodium nitritewere conducted. Quantitative determination was performed by HPLC. Oxidation products were iden-tified by gas chromatography-mass spectrometry in combination with solid-phase microextraction. FDMHwascompletely oxidized by Fenton’s reagent with formation of formaldehyde N-formyl-N-methyl-hydrazone, 1,4-dihydro-1,4-dimethyl-5H-tetrazol-5-one by the action of potassium permanganate and N-methyl-N-nitro-methanamine in the presence of sodium nitrite. Oxidation of FDMHalso resulted in formation of NDMA. Oxidation of DMAANproceeded with formation ofhydroxyacetonitrile, di-methylformamide and 1,2,5-trimethylpyrrole. After 30 days,DMAAN was not detected in the presence of Fenton’s reagent and potassium permanga-nate, but it’s concentration in samples with sodium nitrite was 77.3 mg/L.