Ionic liquid-based solvent systems containing diglycolamide-functionalized calixarenes (C4DGAs) are efficient for actinide ion extraction from nitric acid feeds. Therefore, the radiolytic stability of three C4DGAs (wide-rim, narrow-rim and both side DGA-functionalized calixarenes) and TODGA (N,N,N′,N′-tetraoctyldiglycolamide) (used for comparison purpose), was evaluated by exposing their solutions in an ionic liquid as well as a 95:5 mixture of n-dodecane + isodecanol to gamma radiation up to an absorbed dose of 1000 kGy. Liquid–liquid extraction studies were carried out using 241Am as a radiotracer. Apart from a decrease in the DAm values, ascribed to radiolytic degradation, FT-IR, EPR and GC–MS studies were carried out to characterize the degraded species. The different extractants are less sensitive to radiolytic degradation in the ionic liquid than in the molecular diluent.