The thermal stability of high-Cr Ni-based alloys is a potential concern for the long-term performance of nuclear plants and possibly spent fuel storage containers. Many existing commercial nuclear power reactors expected to operate beyond 80 years use these alloys extensively. Advanced SMRs of both PWR and BWR type will also use high-Cr Ni alloys and are expected to receive initial licenses for 60 years. While several studies were focused on the microstructural changes occurring in the high-Cr Alloy 690 during long time exposure to the reactor operating temperatures, the weld alloys of similar chemistry have received relatively little attention. However, extensive SCC CGR testing conducted over the last decade has found that, in fact, the weldments – especially in first layer/weld butter/weld overlay configurations – could be as susceptible to SCC as the low-Cr weldments even in their non-aged condition. In order to study the effects of aging on weldments, an Alloy 152 dissimilar metal weld (DMW) joining Alloy 690 and Alloy 533 - identical to the one tested extensively in an US NRC research program - was aged over the last decade at three different temperatures (370, 400 and 450°C) for up to 75,000h. Several early aged conditions of this weldment were characterized as part of an I-NERI program, and several trends of the effects of aging on microstructure are already discernible. These microstructural changes affect key, SCC-susceptible areas such as the fusion line. Hence, the purpose of this paper is to discuss the potential effects of aging on areas of known susceptibility, describe current research undertaken at ANL in this area, and highlight areas in need of future investigation.