['To determine the differential impact of maternal and paternal internalizing psychopathology on cognitive-behavioural treatment (CBT) outcome of anxiety-disordered children and adolescents.', 'Participants consisted of 127 children and 51 adolescents with a primary anxiety diagnosis. Children were randomly assigned to a standardized group CBT or individual CBT; adolescents received individual CBT. Parents received four training sessions. Participants were evaluated at pre- and post-treatment with a clinical interview and with self- and parent-reported questionnaires. Lifetime anxiety and mood disorders in parents were obtained with a clinical interview.', 'For children, no associations were found between maternal and paternal anxiety or mood disorders and treatment outcome. For adolescents, however, maternal lifetime anxiety disorders were positively associated with pre-post-treatment improvement in clinician severity ratings and with treatment success.'] Does maternal anxiety predict favourable treatment outcomes in anxiety-disordered adolescents?