To investigate critical care nurses' current practice and knowledge related to pain assessment and management for critically ill adults able and unable to self-report pain. Cross sectional self-report survey. Survey response rate was 57%. Though more respondents used formal pain assessment tools often or routinely for patients able to self-report compared to patients unable to communicate (P<0.0001), there was no difference in perceived importance of pain assessment tools. Nurses were less confident in their ability to accurately assess pain for patients unable to self-report (P<0.0001). Behaviours most frequently considered routinely indicative of pain were grimacing (88/140, 62.9%), vocalisation (78/140, 55.7%) and wincing (73/140, 52.1%). Haemodynamic instability, nursing workload and patient inability to communicate were the barriers considered to interfere with pain assessment and management most frequently. Enablers to effective management included pain prioritisation, and adequate prescription of analgesia. Most respondents (118/140 84.3%) had received continuing education on topics related to pain. Though nurses considered pain assessment equally important for patients unable and able to selfreport, formal assessment tools were used less frequently and nurses were less confident in their ability to assess pain for patients unable to self-report.