BACKGROUND: Missed nursing care (MNC) is a significant global issue in health care, especially in intensive care units (ICUs) where the complexity of patient care and high workloads increase the risk of errors and omissions. Nursing deficits impact patient safety, nurse efficiency and psychological well-being, yet the relationship between ICU nurses' perceptions of patient safety, their caring behaviour, professional self-efficacy and nursing deficits remains underexplored. AIM: This study aimed to examine the relationships between ICU nurses' perceptions of patient safety, caring behaviour, professional self-efficacy and nursing deficits through a multiple mediation model. STUDY DESIGN: A cross-sectional survey was conducted with 304 ICU nurses from general hospitals in Guangxi Province between January 2022 and January 2024. The study used validated instruments to measure patient safety perception, caring behaviour, professional self-efficacy and nursing deficits. Spearman correlation and multiple mediation analyses were applied to explore the relationships among these variables. RESULTS: ICU nurses reported average scores of 63.35 ± 8.06 for patient safety perception, 70.28 ± 12.14 for caring behaviour, 26.19 ± 4.57 for professional self-efficacy and 75.92 ± 17.68 for nursing deficits. Significant negative correlations were found between patient safety perception, caring behaviour, professional self-efficacy and nursing deficits (r = -.483, -.516, -.326, p <
.01). Caring behaviour and self-efficacy mediated the relationship between patient safety perception and nursing deficits, accounting for 74.65% of the total effect. This study follows the STrengthening the Reporting of OBservational studies in Epidemiology guidelines. CONCLUSIONS: This study highlights that improving ICU nurses' perceptions of patient safety can reduce nursing deficits by enhancing caring behaviour and professional self-efficacy, offering a pathway to improve care quality in ICUs. RELEVANCE TO CLINICAL PRACTICE: Hospital administrators should focus on strategies that enhance ICU nurses' safety perception, caring behaviour and self-efficacy to reduce nursing deficits and improve patient outcomes.