Background <p>Shift work leads to an imbalance in nurses’ circadian rhythms, which affects not only nurses’ physical and mental health but also the quality of care and patient safety. Although sleep disturbance among shift nurses has been a research concern, insufficient attention has been paid to the psychological dimension of sleep-related worry. Of particular interest are protective psychological factors such as trait mindfulness, a stable endogenous psychological resource that mitigates stress responses by reducing ruminative thinking and emotional hyperreactivity. However, the association between trait mindfulness and sleep-related worry among shift nurses remains unexplored. This study aimed to investigate the level of sleep-related worry, explore the factors influencing it, and identify the relationship between sleep-related worry and trait mindfulness among shift nurses in Shanxi Province, northern China.</p> Methods <p>A quantitative cross-sectional study was conducted using the Anxiety and Preoccupation about Sleep Questionnaire and Mindful Attention Awareness Scale. The data were obtained from 320 shift nurses in three tertiary general hospitals in Shanxi Province. Descriptive statistics, Spearman correlation analysis, and multiple linear regression analyses were performed for data analysis.</p> Results <p>The median total score for shift nurses’ sleep-related worry was 40.00 (IQR 37.00–44.00), indicating that their sleep-related worries were above the middle. The median total trait mindfulness score for shift nurses was 35.00 (IQR 28.00–45.00). Our findings revealed a significant negative correlation between sleep-related worry and trait mindfulness, suggesting that individuals with lower levels of trait mindfulness (score range 15–74) tend to experience higher levels of sleep-related worry (score range 10–50). Multiple linear regression analyses indicated that shift nurses’ sleep-related worry was significantly associated with age (β= -0.086, 95% CI: -1.887, -0.019), average daily sleep duration (β= -0.199, 95% CI: -3.764, -1.546), monthly frequency of night shifts (β = 0.235, 95% CI: 2.169, 4.607) and trait mindfulness (β= -0.580, 95% CI: -0.361, -0.271).</p> Conclusions <p>Sleep-related worry among shift nurses is a serious concern in Shanxi Province. Trait mindfulness was a significant factor associated with sleep-related worry among shift nurses. Therefore, clinical nursing managers should focus on sleep-related worry among shift nurses, adopt reasonable measures to improve their sleep problems, enhance their trait mindfulness levels, and ultimately reduce their sleep-related worry, thus improving their sleep quality and overall well-being.</p>