This study examined the longitudinal reciprocal effects between health and social support in older adults’ relationships with their children and friends. Data are from the 2006 and 2010 waves of the Health and Retirement Study (N = 3,760). We focused on three specific aspects of social support: frequency of contact, positive interactions, and negative interactions. We used autoregressive cross-lagged models to examine the bidirectional effects between social support and health. When the bidirectional effects between health and social support were simultaneously examined, the longitudinal effect of social support on health was not significant. In contrast, older adults’ poor health was associated with decreased contact and decreased positive interactions with friends as well as with increased negative interactions with their adult children and friends. The findings suggest that older adults’ poor health has a negative impact on their social relationships and that such effect surpasses the impact of social relationships on health.