Background <p>Indoor air pollution has been recognized as a risk factor for mental health, particularly depression and anxiety symptoms. Indoor musty odors are considered a component of indoor air pollution. However, evidence on the associations between indoor musty odors and mental health among older adults is limited.</p> Methods <p>The current study utilized data from the Chinese Longitudinal Healthy Longevity Survey (CLHLS). We employed self-reported data to ascertain indoor musty odors. Depression symptoms were evaluated utilizing the Center for Epidemiologic Studies Depression Scale-10 (CES-D-10), and anxiety symptoms were measured using the Generalized Anxiety Disorder Scale-7 (GAD-7). This study implemented logistic regression and linear regression to examine the associations of indoor musty odors with depression and anxiety symptoms.</p> Results <p>A total of 11,950 older adults (mean age = 83.11 ± 11.12 years) were included in this study. The study indicated that indoor musty odors were significantly associated with depression symptoms (adjusted odds ratio (OR) 1.83, 95% CI 1.58, 2.11) and anxiety symptoms (adjusted OR 2.12, 95% CI 1.78, 2.53).</p> Conclusions <p>These findings provide valuable insights of indoor musty odors into the potential health risks associated with older adults’ depression and anxiety symptoms.</p>