The cross-age effect refers to the finding of better memory for own- than other-age faces. We examined 3 issues about this effect: (1) Does it extend to the ability to monitor the likely accuracy of memory judgments for young and old faces? (2) Does it apply to source information that is associated with young and old faces? And (3) what is a likely mechanism underlying the cross-age effect? In Experiment 1, young and older adults viewed young and old faces appearing in different contexts. Young adults exhibited a cross-age effect in their recognition of faces and in their memory-monitoring performance for these faces. Older adults, by contrast, showed no age-of-face effects. Experiment 2 examined whether young adults' cross-age effect depends on or is independent of encoding a mixture of young and old faces. Young adults encoded either a mixture of young and old faces, a set of all young faces, or a set of all old faces. In the mixed-list condition we replicated our finding of young adults' superior memory for own-age faces; in the pure-list conditions, however, there were absolutely no differences in performance between young and old faces. The fact that the pure-list design abolishes the cross-age effect supports social–cognitive theories of this phenomenon.