The differential activation hypothesis (DAH; Teasdale, 1988) proposes that individuals who are vulnerable to depression can be distinguished from non-vulnerable individuals by the degree to which negative thoughts and maladaptive cognitive processes are activated during sad mood. While retrieval of negative autobiographical memories is noted as one such process, the model does not articulate a role for deficits in recalling positive memories. Two studies were conducted to compare the autobiographical memory characteristics of never-depressed and formerly depressed individuals following a sad mood induction. In Study 1, features of negative memories of never-depressed and formerly depressed individuals did not differ, either in neutral or sad mood. For positive memories, groups did not differ in neutral mood, but following a sad mood induction, formerly depressed individuals rated their positive memories as less vivid than their never-depressed counterparts. Study 2 examined positive autobiographical memory features more comprehensively and replicated the finding that in a sad mood formerly depressed individuals recalled less vivid positive memories than never-depressed controls. These findings suggest that the phenomenological features of positive memories could represent an important factor in depressive vulnerability, and, more broadly, that depression may be associated with a deficit in the processing of positive material.