This longitudinal study of mortality among the elderly (65 and over) in China used a large representative sample to examine the association between mortality and three different socio-economic status (SES) indicators—education, economic independence, and household income per head. The results, while varying depending on the measures used, show that there is strong evidence of a negative association between SES and overall mortality. A cause-specific analysis shows that SES is more strongly related to the reduction of mortality from more preventable causes, such as circulatory disease and respiratory disease, than from less preventable causes such as cancer. We also investigated the effects of three sets of factors that may mediate the observed SES–mortality relationship: support networks, health-related behaviours, and access to health care. The results show that for both overall and cause-specific mortality, access to health care is the most important of the three.