INTRODUCTION: Mother-to-child-transmission of HIV, syphilis and hepatitis B is a significant public health issue in Indonesia. Triple elimination screening, which tests these three infections, is a crucial strategy for early detection and prevention, ideally conducted during the first antenatal visit (K1). However, the coverage of this screening remains suboptimal in several regions, including the Harapan Baru Health Center. This study aimed to test factors affecting participation in the triple elimination screening during the first antenatal visit among pregnant women in the service area of the Harapan Baru Health Center. MATERIALS AND METHODS: A cross-sectional study was conducted involving 50 pregnant women who attended their K1 visit in June 2025. Participants were selected using convenience sampling. Data were gathered through structured questionnaires and maternal and child health (MCH) books and analysed using the Pearson chi-square test. RESULTS: Respondents’ knowledge (OR=5.4, p=0.023) and health worker support (OR=10.7, p=0.002;) were significantly associated with screening participation. However, the education level was not significantly associated. CONCLUSION: Good knowledge level and positive support from health workers could increase the likelihood of pregnant women undergoing triple elimination screening during their first antenatal visit.