It is commonly assumed that as short-term memory tasks become more difficult, a transient phonological trace that supports recall loses its fidelity. Recall can still be achieved through a process called redintegration, where long-term phonological or lexical knowledge is used to reconstruct the memory trace. In the present research, we explored age-related differences in the redintegration process by having older and younger participants study lists under different levels of task difficulty. As a means of examining the redintegration process, in Experiment 1, semantic similarity was manipulated, and in Experiment 2, phonological similarity was varied. The results show that similarity effects can be accurately predicted from knowledge of task difficulty with item scoring, but not with order scoring. The results support the redintegration perspective and indicate that although there may be differences in the absolute level of recall across age groups, the redintegration process is identical for younger and older participants.