Palladium and its alloys have been extensively studied because of their faculty to store reversibly hydrogen isotopes. Here, aging effects on pressure-composition isotherms of Pd(PtRh) solid solutions are investigated for tritium storage up to 5 years. The main changes observed are the decrease of the plateau pressures and the shift of the α and β branches towards greater stoichiometries, as it was already observed for pure palladium. In this study, we show that aging effects are greater on palladium substituted by platinum and/or rhodium than for pure palladium. These observations can be correlated to different evolutions of the structural and micro-structural properties of the solid solutions.