Introduction: Truck drivers are one of the most high risk groups to be exposed to Aids who must have been aware about the dangers of this disease. The destination is not important but Truck drivers’ knowledge is very important. The aim of this study was to assess the knowledge of Truck drivers of AIDs prevention in Iran. Materials and Methods: This is a Cross - sectional study which determines the participant’s knowledge about HIV and Aids transmission and its prevention and then the relationships between these and demographic characteristics have been measured. Samples: 190 Truck drivers going to Iranian cities. Results: Findings showed the most (43.5%) truck drivers’ knowledge was in the average level with Mean value (5.1) and standard deviation (2.2 2). Chi showed positive relationships between knowledge and some variables like educational level, and continent of destination (P < 0.05). Z statistical test and Pearson’s correlation coefficient showed that there is positive relationships between drivers ‘ knowledge and their age (P < 0.05), (r = .14) and between drivers’ knowledge and their informational sources. (P< 0.05), (r = 0.51). Conclusion: Findings showed that drivers didn’t have sufficient knowledge about transmission and prevention of AIDs. So, their health knowledge must be increased for health protection. Therefore training is one of the ways which can be used for increasing drivers’ knowledge.