Many factors affect the characteristics of stickies and their removal from deinked paper pulp. Because most papers have a specific service lifetime and because there is often a time lag between collection and processing for paper recycling, the adhesives on the collected papers can age. This study investigates the effects of the aging of pressure-sensitive adhesives on stickies properties and their removal efficiency during paper recycling. Adhesives coated on the surface of label paper were subjected to accelerated aging with specialized equipment and introduced into paper as the origin of stickies. The results showed that adhesive aging deteriorated the adhesion performance, surface physicochemical characteristics, and elasticity of the stickies particles. The aging had a direct effect on particle size during recycling unit operations. The removal efficiencies of adhesive contaminants during screening and flotation were reduced as a result of adhesive aging. Heterogeneity in the aging composition of stickies mixtures also had a negative effect on their removal behavior.