OBJECTIVES: To summarize the occurrence rates and identified the risk factors for pain at rest and during procedures in critically ill patients. METHODS: This study conducted a systematic review and meta-analysis. The Embase, PubMed, CINAHL Plus, Web of Science Core Collection and ProQuest Dissertations & Theses A&I databases were searched from inception to January 10, 2025, for relevant studies. Two independent researchers screened the articles, reviewed them, and extracted data. The data were analyzed using a random-effects model. RESULTS: This meta-analysis included 23 observational studies with prospective, retrospective, and cross-sectional study designs encompassing 8,073 adult participants. The pooled occurrence rate of pain at rest among critically ill patients was 41 % (95 % confidence interval [CI] = 0.27 to 0.57), whereas that of pain during procedures was 68.4 % (95 % CI = 0.58 to 0.77). Most studies on intensive care unit (ICU)-related pain were conducted in the Asia Pacific region, the Americas, and Western Europe. Age was determined to be negatively associated with pain at rest, whereas opioid use percentage and percentage of male were positively associated with the occurrence of pain during procedures. CONCLUSIONS: Pain at rest and during procedures is highly prevalent and often undertreated in ICU patients. Health-care providers should develop and implement effective pain management strategies to mitigate both pain at rest and procedural pain in critically ill patients. IMPLICATIONS FOR CLINICAL PRACTICE: Pain is a frequent and troubling experience for patients in the ICU, so healthcare providers need to assess and address it regularly. This study also pinpointed specific factors linked to pain at rest and during procedures, some of which can be changed or managed. These results offer ICU medical team valuable insights for identifying high-risk patients and delivering personalized interventions to minimize pain.