OBJECTIVE: To identify evidences of the influence of nursing workload on the occurrence of adverse events (AE) in adult patients admitted to the intensive care unit (ICU). METHOD: A systematic literature review was conducted in the databases MEDLINE, CINAHL, LILACS, SciELO, BDENF, and Cochrane from studies in English, Portuguese, or Spanish, published by 2015. The analyzed AE were infection, pressure ulcer (PU), patient falls, and medication errors. RESULTS: Of 594 potential studies, eight comprised the final sample of the review. TheNursing Activities Score (NAS; 37.5%) and the Therapeutic Intervention Scoring System(TISS; 37.5%) were the instruments most frequently used for assessing nursing workload. Six studies (75.0%) identified the influence of work overload in events of infection, PU, and medicationerrors. An investigation found that the NAS was a protective factor for PU. CONCLUSION: The nursing workload required by patients in the ICU influenced the occurrence of AE, and nurses must monitor this variable daily to ensure proper sizing of staff and safety of care.