<![CDATA[Human Immunodeficiency Virus (HIV) and Acquired Immunodeficiency Syndrome (AIDS) remain serious public health issues globally and in Indonesia. This study aimed to determine the relationship between HIV/AIDS knowledge and risky sexual behavior among Men who have Sex with Men (MSM) accessing services at the Pematangsiantar City Health Office. The study sample consisted of 94 individuals selected via purposive sampling from a population of 1,546 MSM registered with the Pematangsiantar City Health Office. The results showed that the majority of respondents (80.9%) possessed a good level of HIV/AIDS knowledge, while 19.1% fell into the poor knowledge category. Regarding sexual behavior, 57.4% of respondents were classified as low-risk, and 42.6% were classified as high-risk. Chi-Square test results yielded a p-value of 1.000 (p > 0.05) and an Odds Ratio (OR) of 0.909 (95% CI: 0.323–2.560), indicating no statistically significant relationship between HIV/AIDS knowledge and risky sexual behavior among the MSM group at the Pematangsiantar City Health Office. It can be concluded that good HIV/AIDS knowledge is not automatically accompanied by safe sexual behavior among MSM, as sexual behavior is also influenced by factors such as attitudes, self-efficacy, partner pressure, alcohol or drug use, stigma, and access to healthcare services. Therefore, HIV/AIDS prevention programs for MSM should focus not only on increasing knowledge but also on skill-based interventions, strengthening peer support, and reducing stigma within healthcare services]]>
