Gerontological social workers and other health professionals are often dealing with older adults in psychological distress. Greater clarity on the relationship between stress and psychological distress will enhance the efficacy of outreach and treatment initiatives for older adults. This study explored the underlying causal structure of the relationships of common life stressors and psychosocial resources for Canadians 65 years and older (542 men and 835 women). Using structural equation modeling of data collected in the National Population Health Survey in 2004-2005 and 2002-2003, the roles played by socioeconomic conditions, physical health, chronic stress, sense of mastery, and perceived social support in the stress-psychological distress relationship were estimated and compared. Findings revealed that chronic stress was the strongest determinant of the level of psychological distress for both genders; however its effect was higher for men compared to women. Poor physical health played a more important role in determining women's psychological distress compared to men. Higher levels of mastery and perceived social support were associated with lower levels of psychological distress for both men and women. These associations were somewhat stronger for men compared with women. Socio-economic conditions played a minor role in the stress-mental health relationship for both genders.