Background: Healthcare environment can affect health. Adverse events (AEs) are common because rapid changes in the patients' status can suddenly arise, and have serious consequences, especially in intensive care. The relationship between the design of intensive care units (ICUs) and AEs has not been fully explored. Hence, an intensive care room was refurbished with cyclic lightning, sound absorbents and unique interior, and exterior design to promote health. Aims: The aim of this study was to evaluate the differences between a regular and a refurbished intensive care room in risk for AEs among critically ill patients. Design: This study retrospectively evaluated associations of AEs and compared the incidence of AEs in patients who were assigned to a multidisciplinary ICU in a refurbished two-bed patient room with patients in the control rooms between 2011 and 2018. Methods: There were 1938 patients included in this study (1382 in control rooms; 556 in the intervention room). Descriptive statistics were used to present the experienced AEs. Binary logistic regressions were conducted to estimate the relationship between the intervention/control rooms and variables concerning AEs. Statistical significance was set at P < 0.05. Results: For the frequency of AEs, there were no significant differences between the intervention room and the control rooms (10.6% vs 11%, respectively, P < 0.805). No findings indicated the intervention room (the refurbished room) had a significant influence on decreasing the number of experienced AEs in critically ill patients. Conclusions: The findings revealed a low incident of AEs in both the intervention room as well as in the control rooms, lower than previously described. However, our study did not find any decreases in the AEs due to the design of the rooms. Relevance to clinical practice: Further research is needed to determine the relationship between the physical environment and AEs in critically ill patients.