Influence of miscibility between the components in acrylic pressure-sensitive adhesives upon their peel strength P as a function of temperature has been studied. In case of miscible blend systems, incorporation of tackifier resins into the pressure-sensitive adhesive systems results in the modification of the bulk properties, including T-g, and a plot of P against Delta T gives a smooth master curve, where Delta T is defined as the difference between the temperature of peel test and T-g of the blend. However, in case of immiscible blends where two phases exist in the system, no master curve can be obtained, and P of an acrylic copolymer decreases as the tackifier content increases. In this case, physical properties and adhesive performance will be governed by a matrix phase, and a dispersed phase will act as a filler.