Tehran University of Medical Sciences International Journal of Occupational Hygiene 2008-5109 10 3 2018 08 30 135 142 EHSAN GAROSI AJA University of Medical Sciences, Department of Physical Medicine and Rehabilitation, Tehran, Iran. AND Tehran University Medical Sciences, Department of Occupational Health, Tehran, Iran SHARIF NAJAFI AJA University of Medical Sciences, Department of Physical Medicine and Rehabilitation, Tehran, Iran ADEL MAZLOUMI Tehran University Medical Sciences, Department of Occupational Health, Tehran, Iran MOJTABA DANESH Tehran University Medical Sciences, Department of Occupational Health, Tehran, Iran MASOUMEH ABEDI PhD Candidate, School of Health and Rehabilitation Sciences, The University of Queensland, Australia 2019 07 09 2019 10 15 Nurses have always been considered as a unique working group because of the physically and mentally demanding tasks they bear at work. Such a working condition exposes them to a high risk of fatigue, which could influence their work ability. Therefore, this study aims to investigate the relationship between work ability index (WAI) and fatigue of critical care nurses in a military hospital. In this descriptive and cross-sectional study, 101 nurses (71 females and 30 males) of critical care units filled out both the Persian version of WAI and nurses’ fatigue questionnaires. The nurses were selected from three general hospitals of Tehran by cluster sampling method. The Pearson correlation test was used for investigating the relationship between two quantitative variables, and all the statistical analyses were performed by SPSS v. 21 software. The nurses’ average age was 24.5 years old (±SD=±3.6), and the mean of work experience was 9 years (±SD=±4.13). The mean work ability of the nurses was 40.01 (±SD=±4.05), indicating “good work ability”. Fatigue was found in 46.19% of the participants, and the nurses’ fatigue was mainly of mental type (29.8%). There was a significant negative correlation (-0.57) between the scores of WAI and total fatigue (p < 0.001). The negative correlation between WAI and fatigue shows that WAI and fatigue score could be a good predictor of health and quality of work life. Identifying the influential factors of nurses’ work ability and fatigue would help to improve the work condition of critical care nurses. https://ijoh.tums.ac.ir/index.php/ijoh/article/view/395 https://ijoh.tums.ac.ir/index.php/ijoh/article/download/395/578