The relationship between probe tack and fracture energy for SIS (styrene-isoprene-styrene)-based HMPSAs (hot-melt pressure-sensitive adhesives) made using various SIS and tackifiers was investigated. Generally, HMPSAs made using low-T-g tackifiers have higher probe tack than using high-T-g tackifiers, except in the case of Sukorez SU 100. In the case of Kraton blends, blends made using Quintone U 185, Hikorez A 1100S and Sukorez SU 100 exhibit a maximum probe tack at 60 wt% tackifier content, while the blends made using GA-100 and Regalite R 125 exhibit a maximum probe tack at 40 wt% tackifier content. In the case of the Vector blends, similar results are observed, except that those HMPSAs made using Hikorez A 1100S and Sukorez SU 100 have a maximum probe tack at 50 wt% tackifier content. Because tri-bock SIS (Vector 4111) has a higher cohesion than the diblock containing SIS (Kraton D 1107), Vector 4111/tackifier blends exhibit a maximum tack at higher tackifier contents than Kraton D 1107/tackifier blends. In terms of the fracture energy of blends, similar results were observed. Generally, the fracture energy (w) of the SIS-based HMPSAs was closely related to the maximum probe tack. Because of the effects of failure mode on fracture energy and probe tack, there is some variation in the fracture energy between the different blends, because of their different failure modes.