Two studies examined the role short-term changes in adult attachment and mindfulness play in depression and general anxiety. Study 1, using a sample of college students (n = 121) who were not engaged in any clinical intervention, showed that changes in attachment anxiety and security, but not in avoidance, predicted changes in depressed and anxious mood. Study 2, using a college age clinical sample (n = 28), showed that changes in adult state attachment (avoidant, anxious, and secure) predicted reductions in depression, but that only changes in avoidant attachment, not anxious or secure attachment, predicted reductions in general anxiety. These findings suggest that reducing avoidant attachment is particularly important in successful therapy, but plays less of a role in natural fluctuations in depressed and anxious mood in non-clinical settings. Mindfulness predicted changes in depression and general anxiety in both the clinical and class studies. Mediation analyses showed that mindfulness partially mediated the association between adult attachment and depression and general anxiety. Implications for research and clinical practice are discussed.