Three studies investigated the relation between adult attachment security and symptoms of depression. Study l examined the overall magnitude of the association between adult attachment and depression, and Studies 2 and 3 tested whether this relation was mediated by dysfunctional attitudes and low self-esteem. Results from the three studies were consistent with a mediation model. This model suggests that insecure adult attachment styles are associated with dysfunctional attitudes, which in turn predispose to lower levels of self-esteem. Such depletions in self-esteem are directly associated with increases in depressive symptoms over time. Insecure attachment appears to lead to depressive symptoms in adulthood through its impact on self-worth contingencies and self-esteem.