Background and Purpose: One of the most dangerous and life-threatening complications after long-term surgery is Deep vein thrombosis. Surgery can play a specific role in the occurrence of this complication. One of the most important areas in any medical center where patients most deal with DVT complications is the operating room, and the knowledge of the personnel working in this department plays a significant role in preventing this complication. The importance of this issue led researchers to carry out this project with the aim of the determination of the level of knowledge and attitude of operating room personnel about deep vein thrombosis. Materials and Methods: In order to perform this research, a demographic information questionnaire and researcher-made questionnaires were used to evaluate the level of knowledge, attitude, and performance of personnel, and statistical analysis of the data was performed by SPSS software version 21. In order to measure the relationship between quantitative and qualitative variables, independent t-test and ANOVA test were used. Results: The findings of this study showed that the mean and standard deviation of surgical technologists' awareness was obtained at 44.96±8.05, which according to the Likert scale, the level of awareness was desirable. The mean and standard deviation of the attitude of surgical technologists was obtained at 17.41±3.92, which according to the Likert scale was a positive attitude, and the mean performance of the surgical technologists was obtained at 18.93±4.5, which according to the Likert scale was the level of intermediate. Conclusion: In general, the implementation of DVT prevention protocol by hospitals may not be enough to reduce this complication in patients after surgery. The design and implementation of a training program on DVT prevention should be regularly required for all surgical technologists working in hospital operating rooms.