Abstract: STUDY OBJECTIVES: Suicide rates among U.S. military Veterans with posttraumatic stress disorder are high. This study provides a preliminary test of extended, objective assessment of in-home sleep to enhance the prediction of variation in suicidal ideation severity. METHODS: An inexpensive, mailable, mattress actigraphy system was used to record in-home sleep of Veterans at high and low risk for suicide. Recruitment was accomplished through access to national registers maintained by the Department of Veterans Affairs. After telephone-guided setup, participants did not interact with the measurement system. Actigraphic data were uploaded to the cloud nightly. Self-report measures were gathered at baseline and weekly throughout participation. Questions addressed were 1) group differences in demographics and psychometrics (n = 54 high-risk/21 low-risk), 2) group differences in objective sleep scheduling (n = 46 high-risk/18 low-risk), 3) within-group associations between changes in sleep and changes in suicidal symptoms (n = 46 high-risk), and 4) covariance between week-to-week changes in sleep and suicidal ideation (n = 46 high-risk). RESULTS: The high- and low-risk groups differed on measures of depression and suicidality. High-risk Veterans went to bed 63 min earlier than low-risk participants. Within the high-risk group, total minutes-in-bed and out-of-bed times were negatively correlated with measures of suicidal ideation and cognition. Within that group, earlier in-bed times were modestly predictive of increased suicidal symptoms even after accounting for self-reported depression. CONCLUSIONS: Aspects of sleep may be recorded in moderately suicidal persons using fully remote, zero-burden methods. Observed associations highlighted potential relevance to suicide surveillance and prevention.