How do grandparents spend their child-care time? We examine how the composition of grandparent child care differs from parent child care, and whether child-care composition is more gender-similar for grandparents than for parents. Using the most recent (2006) Australian Bureau of Statistics Time Use Survey, we investigate along three dimensions: (a) the activities child care consists of (routine versus non-routine), (b) whether it is multi-tasked (and whether it is paired with productive activities or with leisure), and (c) whether it is done solo or with a partner present. We find fathers and grandmothers' active child care is similarly apportioned between routine and non-routine activities, while mothers spend much more, and grandfathers spend much less, of their child-care time in routine care activities. Fathers and grandfathers spend similar proportions of their child-care time multi-tasking with leisure (about 50%) and performing care without their spouse present (about 20%), differing significantly from women on both these measures. Gender differences in the proportion of child care multi-tasked with productive activities (paid work, domestic work or other child care) are the same in both generations, but gender differences in the proportion of child care that is spent in routine activities, and that is done without a partner present, are significantly less for grandparents than for parents. The narrower gender gaps result from grandmothers spending less of their child-care time on these measures than mothers, not from grandfathers spending more of their child-care time on these measures than fathers.