BACKGROUND: Cognitive behavioral therapy for insomnia (CBT-I) has been shown to improve depressive symptoms in older adults with comorbid insomnia and depression. However, it remains unclear whether brief CBT-I is effective for improving depressive symptoms in community-dwelling older adults with insomnia symptoms of varying severity. AIM: This study sought to examine the effectiveness of a brief CBT-I intervention delivered by public health nurses to improve depressive symptoms among older adults recruited from a community setting. METHODS: This randomized controlled study compared sleep status and depression at baseline and a 3-month follow-up using a wait-list control design. Depression was evaluated using the Geriatric Depression Scale short form (GDS-SF). RESULTS: The GDS-SF scores in the CBT-I group improved over time (p < .01), with an effect size (Cohen's d) of 0.34 (95% CI [0.16, 0.58]). The results demonstrated the effectiveness of a brief CBT-I intervention for depression, although the effect size was small. LINKING EVIDENCE TO ACTION: A brief CBT-I intervention consisting of sleep hygiene education, stimulus control, sleep restriction, cognitive restructuring, and relaxation is effective for improving depressive symptoms among older adults in the community.