The relationship between social network structural and support characteristics and onset of new or recurrent activities of daily living (ADL) disability was examined in a cohort of older men and women. No significant protective effects were found for network structural or support characteristics. However, greater frequency of instrumental support was associated with significantly increased risk of ADL disability among men; a similar though nonsignificant pattern was seen among women. These findings indicate that receipt of more instrumental support may not have uniformly beneficial effects on functional status. They serve to underscore the need for more comprehensive research, examining both the positive and negative effects of social interactions on health and functioning.