To examine the longitudinal relationship between past-year problem-gambling severity and incident Axis I psychopathology among older adults (aged 55-90), analyses were conducted on data from the National Epidemiologic Study of Alcohol and Related Conditions (NESARC). This nationally-representative population-based survey was conducted in two waves (Wave 1, 2000-2001; and Wave 2, 2004-2005). Past-year problem-gambling severity at Wave 1 and incident Axis I psychopathology at Wave 2 were evaluated with the Alcohol Use Disorder and Associated Disabilities Interview Schedule-Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition. Multivariate logistic regression modeling was conducted on groups categorized into low-frequency gambling/non-gambling (LFG/NG), low-risk gambling (LRG), and at-risk/problem/pathological gambling (ARPG) based on DSM-IV criteria for pathological gambling. Relative to LFG/NG, ARPG at Wave 1 was positively associated with the incidence of generalized anxiety disorder (OR = 2.51; p = .011) and any substance use disorder (OR = 2.61; p = .0036); LRG was negatively associated with the incidence of hypomania (OR = 0.33; p = .017). Models were adjusted for demographic characteristics, psychiatric comorbidity, health behaviors, physical health, and stressful life events assessed at baseline. While gambling may represent a positive activity for some older adults, data suggest that risky/problematic gambling behavior may be associated with the development of psychiatric problems in this population. Older-adult gamblers, as well as their clinicians, friends, and family, should be aware of potential risks associated with gambling, adopt strategies to prevent the onset of secondary disorders, and monitor themselves and others for signs of problems.