OBJECTIVE To examine the prevalence and safety of infant second-sleep practices. METHODS A cross-sectional online survey of parents with infants ≤12 months assessed parent-reported sleep practices: position, use of a separate sleep surface, and sleep location at 2 time points (sleep onset and after nighttime waking). A composite score examined if all 3 safe sleep practices were used at each time point. Safe sleep was defined as: supine position, sleeping in a separate space, and in a crib, bassinet, cradle, or playard. Wilcoxon sign rank test was used to examine changes between the time points. Poisson regression models compared parents who reported a second-sleep location with those who did not. RESULTS Of participants (n = 1500), 74% were female, 65% were White, 12% were Black, and 17% were of Hispanic ethnicity. Thirty-nine percent (n = 581) reported a second-sleep practice. Of parents who reported a second-sleep practice, 28% (n = 137) met all 3 safe sleep criteria at sleep onset; 9% (n = 42) met all 3 safe sleep criteria at both time points. A higher proportion of changes in sleep practices were to less-safe practices (P <.001). Factors associated with a second-sleep practice were parental age <25 years, parental race and ethnicity, first-time parents, homes with smoke exposure, and infants born at <37 weeks. CONCLUSIONS Less than 10% of infants met all 3 safe sleep criteria at sleep onset and after nighttime waking. Interventions focused on safe sleep should highlight the importance of safe sleep practices after nighttime waking.