Professional quality of life is associated professional well-being and performance. Otherwise, sleep disturbance has been a common problem for nurses in intensive care unit, which influences the professional quality of life. The purpose of this study was to investigate the relationship between the sleep disturbance, mindfulness and professional quality of life among nurses working in ICU and the effect of mindfulness as a moderator. A cross-sectional study design was conducted to collect data by a structured questionnaire with convenient sampling. The participants, ICU nurses were recruited from a medical center in Taipei City. The data was collected by four questionnaires including characteristics, Professional Quality of Life-5, Pittsburgh Sleep Quality Index, and the Five Factor Mindfulness Questionnaire. 97 subjects were recruited. we found that scores of both positive (Compassion satisfaction) and the negative (Secondary Traumatic Stress & Burnout) components of the professional quality of life were around medium, indicating these are needed to be improved. About 80% of nurses in ICU have sleep disturbance, and the average score of mindfulness is 121.94±9.93. The results showed that sleep disturbance was positively correlated with secondary traumatic stress and burnout. In addition, mindfulness was positively correlated with compassion satisfaction, and negatively correlated with secondary traumatic stress and burnout. Mindfulness wasn’t a moderator on the professional quality of life and sleep disturbance. However, we found mindfulness could help nurses to have more positive feelings toward their work in providing care to patients, which might help them to improve their professional quality of life.