Background: Ergonomic factors predispose nurses to low back pain (LBP). Few studies have clarified the role of workplace violence in LBP occurrence. Objectives: The present study was designed to investigate acute and chronic LBP in Iranian nurses and its association with exposure to physical violence as well as its personal and ergonomic risk factors. Materials and Methods: In this analytical cross sectional study, the rate of acute and chronic LBP and contributing factors were investigated among 1246 nurses using a validated questionnaire. Statistical analysis was performed by chi square, student t-test, and logistic regression, to determine the association between independent variables and LBP. Results: In total, 1246 nurses, consisting of 576 (46.23%) males and 670 (53.77%) females, were included. The mean age and the mean years of employment were 31.23 ± 5.33 and 16.18 ± 7.05, respectively. Both acute low back pain and chronic low back pain were associated with physical violence experience. Moreover, acute and chronic LBP were predicted by positive past history of LBP as well as two ergonomic factors, frequent bending and frequent carrying of patients. Conclusions: Besides a history of low back pain and ergonomic factors, physical violence may be considered a contributing factor for acute low back injuries. Special attention to all personal, occupational, and psychological risk factors is recommended.