Factors influencing expansion of instrumental activities of daily living (IADL) caregiver networks beyond the spouse/partner were studied, using data from the Asset and Health Dynamics among the Oldest Old (AHEAD) nationally representative sample of American elders (ages 70 and older). Analyses were based on 427 Black and White couples in which one partner regularly received IADL assistance; nearly 20% had expanded networks. Logistic regression showed expanded networks were significantly more likely when spouses had IADL or basic personal activity of everyday living (ADL) limitations and help recipients were wives or had numerous IADL or ADL limitations; they also tended to be more common (p <.10) for couples with numerous nearby daughters and help recipients with proxies and those without serious cognitive problems. Network expansion was unrelated to recipients' number of health conditions and Medicaid coverage or couples' ages, marital duration, income, and number of proximate sons. Implications for service programs and caregiving theories of the circumstances linked to IADL assistance from outside the marital dyad are discussed.