Purpose/Objective: To explore demographic, clinical, and psychological factors in intensive care unit (ICU), including self-reported sleep quality and experiences that were associated with posttraumatic stress (PTS) symptoms 6 months after discharge from hospital. Research Method/Design: A prospective survey was conducted (N = 222). On the day of transfer to the hospital ward, ICU patients reported pain and state-anxiety levels, as well as ICU and prehospital sleep quality. Two months after hospital discharge, they reported sleep quality at home and experiences in ICU. Six months after hospital discharge, sleep quality, PTS symptoms (measured with the Posttraumatic Stress Disorder Checklist–Specific; PCL-S; VA National Center for PTSD, 2014) and psychological well-being (using Depression, Anxiety and Stress Scales−21; DASS-21; Ware, Kosinski, & Keller, 1994) were reported. Descriptive data analyses were performed and factors associated with PTS symptoms were explored with multiple linear regression. Results: The sample was predominately male (65%), with a mean age 57 years. At baseline, pain intensity was low (M ± SD; 2.25 ± 1.14) and state-anxiety levels were moderate (2.50 ± 2.90). At 6 months, 30% of the sample demonstrated depression, and 13.5% (mean PCL-S score: 26.54 ± 10.52) reported symptoms reflective of PTS. The regression model explained 68.2% of the variance in the PCL-S score. Higher PTS scores were independently associated with frightening experiences in ICU, higher stress and depression scores, pain intensity at baseline, and sleep quality at 6 months. Conclusion/Implications: Continuing symptoms of PTS were evident in 14% of the cohort. Screening for prevention and treatment of delirium while a patient is in ICU is essential, and psychological screening and follow-up during recovery would therefore also be beneficial for many patients.