It has become increasingly recognized that insufficient sleep is associated with adverse health outcomes. Studies have observed that sleep duration and daytime sleepiness varies by sex and marital status. Few studies have examined the impact of the number of children on sleep. To evaluate the association of marital status and number of children with insufficient sleep and in a large national sample. We analyzed data from the 2008 Behavioral Risk Factor Surveillance System (BRFSS) survey, a population-based telephone survey of non-institutionalized US adults (N = 395,407), in which respondents were asked, "During the past 30 days, for about how many days have you felt you did not get enough rest or sleep?" We used sex-specific, multivariate logistic regression analyses to assess the associations of marital status (married, previously married, never married) and the number of children in the household with frequent insufficient sleep (≥14 days in past 30 days) after adjusting for age, race/ethnicity, and education. In this study population, 23% were never married, 60% were married, and 17% were previously married. Forty-three percent reported having children aged <18 years in the household. Married men (24.3%) were less likely to report frequent insufficient sleep than never married men (28.0%) or previously married men (28.8%). Never married women (33.4%) were more likely to report frequent insufficient sleep than currently married (29.0%) or previously married women (29.0%). The likelihood of frequent insufficient sleep increased in a linear fashion with the number of children in the household for all subgroups (P < 0.05) except among never married men. These findings suggest that the presence of children in the household often increases the frequency of insufficient rest or sleep among the adults with whom they reside. Thus, health care providers may wish to consider the presence of children under 18 years of age a potential "risk factor" for insufficient sleep when counseling adults in the household about the importance of sleep to overall health.