Objective. To explore the relationship between knowledge level and occupational risk exposure to HIV/AIDS in primary care health workers. Methodology. Analytical cross-sectional study. 720 health workers from Santiago answered a survey about HIV/AIDS that included: knowledge level (appropriate, inappropriate), occupational risk (with or without risk), and control variables (age, gender, health center, education and marital status). Descriptive and association analysis were performed. Odds Ratio (OR) was estimated through simple and multiple regressions logistics. Results. 58.7% of the participants reported HIV occupational risk. 63.8% of the participants from the exposed group reported an appropriate level of knowledge, versus 36.1% of the non-exposed group (Adjusted OR of 3.1, IC95%OR: 2.0-4.8, p < 0.0001). Technicians and cleaning staff reported a lower proportion of appropriate level of knowledge compared to the employees with college education (p < 0.0001). Conclusion. The level of HIV/AID occupational risk is directly associated with the level of knowledge of the disease.