STUDY OBJECTIVES:: Although reports of sleep disturbances are common among individuals with posttraumatic stress disorder (PTSD), results of polysomnographic (PSG) studies have inconsistently documented abnormalities and have therefore suggested â€œsleep state misperception.â€ The authors' study objectives were to compare sleep parameters measured objectively and subjectively in the laboratory and at home in civilians with and without trauma exposure and PTSD. DESIGN:: Cross-sectional study. SETTING:: PSG recordings in a sleep laboratory and actigraphic recordings in participants' homes. PARTICIPANTS:: One hundred three urban-residing African Americans with and without trauma exposure and PTSD who participated in a larger study. INTERVENTIONS:: N/A. MEASUREMENTS:: Sleep parameters (total sleep time TST], sleep onset latency SOL], and wake after sleep onset WASO]) were assessed using laboratory PSG and home actigraphy. A sleep diary was completed in the morning after PSG and actigraphy recordings. Habitual TST, SOL, and WASO were assessed using a sleep questionnaire. The Clinician Administered PTSD Scale was administered to assess participants' trauma exposure and PTSD diagnostic status. RESULTS:: Participants, regardless of their trauma exposure/PTSD status, underestimated WASO in the diary and questionnaire relative to actigraphy and overestimated SOL in the diary relative to PSG. Among participants with current PTSD, TST diary estimates did not differ from the actigraphy measure in contrast with those without current PTSD who overestimated TST. No other significant group differences in discrepancies between subjective and objective sleep measures were found. CONCLUSIONS:: Discrepancies between subjectively and objectively measured sleep parameters were not associated with trauma exposure or PTSD. This challenges prior assertions that individuals with PTSD overreport their sleep disturbances. CITATION:: Kobayashi I; Huntley E; Lavela J; Mellman TA. Subjectively and objectively measured sleep with and without posttraumatic stress disorder and trauma exposure. SLEEP 2012;35(7):957-965.