The effect of piperylene-styrene copolymer (PSC) content on the bulk and surface properties of polychloroprene (CR) adhesive was investigated by different methods. Addition of PSC improves adhesion and strength properties of CR. PSC slightly deteriorates thermal stability of CR. X-ray diffraction, UV, and IR spectroscopies studies showed that no chemical interaction between CR and PSC phases occurs. Distinct bulk and surface structure of modified adhesive is caused by the high surface energy difference between CR and PSC phases. By AFM force-distance curve measurements it was deduced that the differences between pull-off force values of modified CR film surfaces in contact with air and backing was related to the enrichment of the higher surface energy component at the backing/film interface. The properties and structure of boundary layers of adhesive modified by high surface energy polymeric additive are essential for the adhesion behavior.