The surface plasmon resonance method was used for determination of 9-(5’-ferrocenylpentanoyloxy) nonyl disulde(FPONDS) and lipase thin lm thicknesses and optical constants. Surface plasmons were excited in the Kretchmann con-guration on the thin 50 nm gold lm on the BK7 or SF10 glass prism. Sufcient sensitivity of the method for investigation oflipase interaction with a thin FPONDS layer (d= 2.9 nm) kinetics was demonstrated. From the experimental plasmon minimumshift to higher angles it could be concluded that lipase is adsorbed on the FPONDS and as a result it causes an increase in theeffective layer thickness. The obtained results are important in understanding the interaction of these molecules, determinationof their size and distribution on the surface.