Objective: To evaluate patient post-intensive care syndrome (PICS-P) and caregiver burden 3 months after discharge from the Intensive Care Unit (ICU) and determine the impact of different components of PICS-P upon caregiver burden. Design: A prospective observational study was conducted over 26 months (January 2013–February 2015). Setting: Medical-surgical ICU and follow-up consultation in Portugal. Patients or participants: Patients discharged after a minimum of 2 days in the ICU. Caregiver inclusion criteria: not paid, written and spoken Portuguese, and agreement to participate in the study. Main variables of interest: In ICU: Patient gender, age, severity of illness (SAPS II) and length of ICU stay. At 3 months caregiver burden, physical (reduced mobility, weakness acquired in the ICU) and psychological components of PICS (anxiety, depression, post-traumatic stress disorder). Results: A total of 168 caregivers completed the survey (response rate of 69%). A low degree of overburden was reported by 34.5% of caregivers, while 15.5% showed moderate to high levels of overburden. Patient anxiety and depression 3 months after ICU discharge significantly influenced the presence of caregiver burden (p=0.030 vs p=0.008). When physical components of PICS-P were evaluated, no influence on caregiver burden was observed. Patient demographics, severity of illness and length of stay also failed to influence caregiver burden. Conclusions: The presence of psychological components of PICS-P 3 months after ICU seems to have a negative impact upon caregiver burden. On the other hand, physical problems showed no important impact upon caregiver overburden.