Cancer is increasingly being seen as a disease that is preventable and manageable. Knowledge often does constitute one element in the behavior change process. In addition, to promote the cancer prevention programs, data on level of knowledge among the target population are needed. The present research (as the first) aimed at providing information on level and correlates of awareness of cancer risk factors among the general public in Iran. The level of knowledge about 12 cancer risk factors (as a section of a multipart questionnaire) was assessed in a representative sample of 2500 adults (aged >18 years) in Tehran, Iran. The data were analyzed using latent class regression with the R statistical package. A small proportion of the respondents (12.2%) had high knowledge level and most of them had mixed (56.9%) and low level of awareness (30.9%). The most important determinants of knowledge level included level of education, gender, and family history. The results provided valuable clues and guidelines toward the formulation of relevant cancer prevention strategies, especially within the scope of health education. The applied statistical model presented a new descriptive and analytical perspective to evaluate the level of knowledge about the cancer risk factors and its determinants.