In a longitudinal study of the network characteristics that assist elderly individuals to meet their needs, as well as the effects of change in four categories of social network dimensions (social interaction, network structure, member attribute, environmental attribute), 133 elderly residents of 18 midtown Manhattan single room occupancy (SRO) hotels were interviewed twice over a 1-year period. The subjects were 58 men, 75 women and 93 percent white. Physical and mental health and social functioning were assessed through the Comprehensive Assessment and Referral Evaluation. Social interaction data were obtained from the Network Analysis Profile. An analysis of the results showed that although all groups met at least four-fifths of their total needs, those in poor health (PH) or undergoing more stress (HS) had more difficulty in meeting their needs than their low stressed (LS) and healthier (GH) counterparts. For the former groups, inability to meet needs at the first interview was significantly related to failure to meet needs at the second interview. Social networks contributed substantially to explaining ability to meet needs among those in the PH/HS group, with interactional, structural, and environmental attributes showing substantial increases in variance. For the GH/LS groups, significant increments in variance occurred primarily within the interactional sphere. The findings confirm the direct, buffering and non-linear effects of social networks. (BL)