Excess specific heat, C-p(E), of binary mixtures of selected components of plant cuticular waxes has been determined. This thermodynamic parameter gives an explanation of the special molecular arrangement in crystalline and amorphous zones of plant waxes. C-p(E) values indicate that hydrogen bonding between chains results in the formation of amorphous zones. Conclusions on the self-asembly process of plant waxes have been also made.