We examined the differential impact of chronic versus acute economic stress on depressive mood among a sample of 1241 low-income, single, European and African American women. Based on Hobfoll's (1988, 1989) conservation of resources (COR) theory, we predicted that acute resource loss would be more distressing than chronic economic lack. That is, although chronically impoverished conditions are stressful, the attendant resource losses created will be more distressing. We further predicted that mastery and social support would be more beneficial in offsetting the negative consequences of acute resource loss than the negative consequences of chronic economic lack, because acute loss creates identifiable demands that resources may address. Hence, we hypothesized that mastery and social support would show stress buffering effects only for material loss, not chronic lack. The findings generally supported the hypotheses, but mastery buffered only European American women's resource loss and social support buffered only African American women's resource loss. The findings are discussed in light of implications for prevention within theoretical and cultural contexts.