Background: Nurses in intensive care units (ICUs) care for critically ill and dying patients. The stressful nature of the work performed by these nurses may affect their spiritual health and sleep quality. Purpose: The purpose of this correlational study was to explore the sleep quality, spiritual health, and related factors in a sample of ICU nurses. Methods: A cross-sectional correlational design with stratified random sampling was applied. A total of 170 clinical nurses were recruited from the ICUs of a medical center in northern Taiwan. A demographic characteristics questionnaire, the spiritual health scale-short form, and the Pittsburgh Sleep Quality Index (PSQI) were used for data collection. Results: The average PSQI score was 7.07, with 62.9% of the participants reporting poor sleep quality. A significantly negative correlation was identified between the spiritual-health-scale item “connections to others” and the PSQI. “Connections to others”, “chronic diseases”, and “menstrual cycle discomfort” were the important predictive factors of sleep quality in the ICU nurses in this study. Conclusions/Implications for practice: The findings of this study support nurses engaging in regular exercise that is both low-intensity and not subject to time or space restrictions in order to help prevent chronic diseases and relieve dysmenorrhea. Furthermore, education and training related to spiritual health should be incorporated into the wholeperson education curriculum in order to enhance spiritual status and improve sleep quality.