Controlling interfacial tension during the processing of blends is critical to developing morphologies that will yield consistent and acceptable mechanical properties. Determination of the interfacial tension is important in developing a predictive understanding of the effects of processing conditions on the morphology and the physical properties of multicomponent systems. The focus of the research reported herein was to investigate the temperature dependence of the interfacial tension for blends composed of polycarbonate (PC) and polyethylene (PE). The effects of temperature were characterized by direct measurements of the interfacial tension using the imbedded fiber retraction (IFR) method. The interfacial tensions of PC/PE were measured at 210, 220, 230, and 240 degrees C. The temperature dependence of the interfacial tension was found to be -0.018 +/- 0.006 dyn/cm-degrees C. In general, the interfacial tension, evaluated for low-viscosity simple fluids, is commonly a weak function of temperature (on the order of 0.01 dyn/cm-degrees C). The results found in this study are in accord with those findings.