This study (1) developed and tested the Socially Supportive Activity Inventory (SSAI) to assess the quantity and quality of socially supportive activities that institutionalized elders receive, and (2) tested the predicted relationships among the variables proposed in the hypothesized causal model, socially supportive activities, self-transcendence, and depression in institutionalized elders. For pilot testing psychometric properties of the SSAI, the content validity was 0.96. Test-retest reliability from a sample of 10 participants yielded stability coefficients of 0.76-1.00, indicating the SSAI is a highly relevant and reliable culturally-based instrument. In the main study, a total of 196 participants were recruited from eight elder care institutions. The results showed an elder's expectation of filial responsibility did not have a moderating effect on the willingness to be/remain institutionalized and on perceived stress. An elder's acceptance of institutionalization was significantly related to perceived stress and indirectly affected depression. The mediator effect of self-transcendence on the relationship between perceived stress and depression was supported. The participation of elderly residents in socially supportive activities demonstrated a moderating effect on the strength of a negative relationship between perceived stress and self-transcendence. In the modified model, an elder's willingness to remain institutionalized, perceived stress, and self-transcendence were significant predictors of depression, accounting for 54.7% of variance. Self-transcendence was the best predictor of depression. These findings contribute to an awareness of importance of culture factors as potential stressors. These findings also help to explain how the psychosocial mechanism of participation in socially supportive activities and the perception of self-transcendence act on depressed elders.