The possibility of synthesis of novel aminomethoxy derivatives of 1-(3-methylphenoxy)-3-ethylthiopropane based on Mannich reaction of 1-(3-methylphenoxy)-3-ethylthiopropane-2-ol and formaldehyde in the presence of secondary amines has been investigated. The structure of synthesized compounds have been proved by the method of elementary analysis, IR and ¹H NMR spectroscopy and mass-spectrometry. Synthesized compounds have been tested as antimicrobial additives to lubricants and antisepticals against bacteriams and fungi. It is established, that they effectively destroy the activity of microorgonisms.