Received wisdom, some sociological theory and a handful of qualitative studies suggest that the "night shift" of caregiving work that interrupts sleep is a burden borne disproportionately by women. However, there is no broadly representative evidence to substantiate claims about who takes the night shift in contemporary American households. Analyses using data from the nationally-representative 2003-2007 American Time Use Surveys show that net of age, paid work commitment, partnership status and the presence and age of dependents, working mothers were significantly and substantially more likely to get up for the night shift than working fathers. These results suggest that the sleeping hours, which make up a third of every day, are an understudied but important site for micro-level processes that reflect and reproduce gender stratification. (Contains 5 tables, 1 figure, and 5 notes.)