Rapid increases in the proportion of older adults in the population present major challenges to policy-makers worldwide. Using a nationally representative sample from the PAPFAM survey in Lebanon, this study examined the living arrangements of older adults (aged > or = 65 years), and their correlates, with a focus on co-residence with married children. Of 1774 older adults 17.1% co-resided with their married children: 28.1% of the 559 unmarried (widowed/divorced/single) and 11.3% of the 1071 married older adults. Among both the married and unmarried, the likelihood of co-residence was significantly lower in regions outside the capital and decreased with increasing socioeconomic status. Among the unmarried elderly, co-residence with a married child was also significantly associated with increasing age and availability of sons, as well as presence of a vascular disorder and speech problems. While solitary living has traditionally been the focus for policy-makers, older people living with a married child may also be a vulnerable group.