Recent evidence on the relationships between people's social support resources and their health shows the general importance of social support as an environmental factor promoting good personal and public health. The literature on social support is less equivocal in this sense than that on health-service use, where some evidence suggests that, even controlling for previous health status, use of the health services is not health promoting. However, it is not clear just what aspects of social support may be relevant to different measures of health status. The relationships between class inequality, social support and health-service use also require illumination. This paper uses longitudinal data from a study of socially disadvantaged households to explore these issues in relation to the health of women and young children. Analysis of these data shows that the social support resources of mothers generally decline over the first year following birth. Both quantitative and qualitative indicators of support are significant predictors of good health, though qualitative indicators (how support is experienced) have stronger relationships with health outcomes than quantitative indicators (the extent of social contact). The psychological well-being of mothers is more closely linked than either their physical health or that of their babies to their support resources. Support from mothers, friends and a research-provided midwife support intervention is particularly important. Health-service use and social support are not related to each other and, indeed, appear to function in opposite ways in relation to health outcomes; while health-service use is associated with poorer health (controlling for social deprivation, stress, and previous health status), the social support resources of mothers are associated with improved health outcomes.