Abstract:                                                                        
Background: The body mechanic is the combined use of body parts to produce movement and maintain balance. The use of good body mechanics promotes effective use of tissue and keeps energy with the knowledge of the proper use of their muscles Aim of the Study to assess the nurses' knowledge and practices towards uses of body mechanics and barrier to do not use it. Design: A descriptive design Setting: The study was conduct at Sohag University Hospital. It was encompassed all nurses in medical and surgical units Sample: A convenience sample was included of (247) nurses who working at Sohage University Hospital. Tools: Four tools were used for data collection. Tool (I): Structured Interview Questionnaire sheet. Tool (II): Assess Knowledge questionnaire sheet. Tool (III): The body mechanics observational checklist. Tool (v): Barriers of unused of body mechanics questionnaire. Results: The findings of the study clarified that most of nurses were females and (49.8%) married. With mean age was (24.9 ± 13.16) .while, (67.6%) do not have any information about body mechanics technique and (99.6%) of nurses who performed moving the patient to the side of the bed without an assistant bathing, moving the patient to sitting position in bed and (94.7%) preparing bed making of patient and moving the patient to standing position with unsatisfactory. The present study also revealed that there was statistically significant difference between age and knowledge, while there was no statistically significant difference between knowledge and sex, level of education. conclusion: The findings of the study revealed that majority of sample had no training, and also nurses don't understanding important of practicing body mechanics. Although they know the importance of body mechanics. So they were faced barrier during performing their work Recommendations: provide enough supply the health facilities of patient-lifting devices which have been shown to be effective in decreasing costs and workdays lost to back injuries and pain among nurses and formation of continuous, planned and competent in-service occupational health programs for nurses on body mechanics