Introduction: Nurses as the major group of health service providers need to have the satisfactory mental health in order to give desirably care for the patients. Therefore this study was done aimed to predict of psychological strain based on perceived work difficulty, occupational hardiness and spirituality among nurses working in hospitals of Malayer.

Methods: The research was descriptive and from correlation type. The statistical population included all nurses working in hospitals of Malayer in 2016 year that 115 people were selected using convenience sampling method. Psychological Strain Questionnaire (PSQ), Work Difficultly Scale, Occupational Hardiness Questionnaire (OHQ) and Daily Spiritual Experience Scale (DSES) were used for gathering data. Pearson correlation, multivariate stepwise regression and software SPSS-22 were used for analyzing the data.

Results: The results showed that there was a significant correlation between perceived work difficulty, component of challenge from occupational hardiness and spirituality with psychological strain (p<0/01), but there wasn't a significant correlation between components of control and commitment from occupational hardiness with psychological strain. Also inter regression analysis results showed that perceived work difficulty, component of commitment from occupational hardiness and spirituality can explain totally %59/7 of psychological strain variance, but components of control and challenge from occupational hardiness cannot predict psychological strain.

Conclusion: According to findings of this study, can suggested training and intervention on improving perceived work difficulty, component of commitment from occupational hardiness and spirituality of nurses as an effective way on decreasing their psychological strain.