Purpose: Pathological gambling is an increasing public health concern, but very little is known about this disorder in older adults. This study evaluated gambling and psychosocial problems across age groups in treatment-seeking gamblers. Design and Methods: At intake to gambling treatment programs, 343 pathological gamblers completed the Addiction Severity Index (ASI) and gambling questionnaires. Participants were categorized by age into young adults (ages 18-35 years; n = 97), middle-aged adults (ages 36-55 years, n = 197), and older adults (aged older than 55 years, n = 49). Differences in demographics, gambling variables, and ASI composite scores were compared across the groups. Results: The middle- and older age gamblers were more likely to be female (45%-55%) than were the younger gamblers (23%), but the groups were similar with respect to most other demographic variables. When controlled for gender, older age was associated with increased employment problems, but fewer social, legal, and substance-abuse difficulties. Compared with middle-aged gamblers, older gamblers wagered on fewer days. Age x Gender effects emerged in onset of gambling problems and amount spent gambling. Older women did not begin gambling regularly until an average age of 55 years, whereas older male gamblers generally reported a lifelong history of gambling. The older female gamblers also wagered the greatest amounts in the month prior to treatment entry. Implications: These data suggest that older adults compose a minority of treatment-seeking gamblers, but differences in psychosocial problems across the age groups may suggest the need for interventions tailored to particular issues encountered by older pathological gamblers. Specifically, treatments focusing on later life development of problems may be indicated for older female gamblers.