The Separation Anxiety Daily Diary (SADD; Allen et al., 2010) assesses parent–child separations that are anxiety-provoking (anxious separations) or non-anxiety-provoking (nonanxious separations) for children along with associated distress, thoughts, and behaviors (e.g., "Clung to parent"). The SADD also covers parental anxiety, thoughts, and avoidance given the role these factors may play in maintaining child anxiety (e.g., "My child will be traumatized if I go"). SADD items were selected on the basis of behavioral analysis (i.e., situations, thoughts, feelings, behaviors, consequences) and guided by factors identified as important in the maintenance of child anxiety (Chorpita & Barlow, 1998; Hudson & Rapee, 2004; Rapee, 2001). Diaries designed for socially anxious children and anxious adults served as models (e.g., Beidel et al., 1991; Margraf, et al., 1987). Selection of item stems for maternal thoughts and child reactions in response to parent–child separation were based on the findings of a pilot study. The SADD was evaluated using clinical and control samples of mothers and children. Findings showed that the SADD can discriminate children with separation anxiety disorder from healthy control children. The SADD also demonstrated evidence of clinical utility and convergent validity.