Background: : According to the World Health Organisation, Lao PDR was among the top 10 countries with the highest reduction in maternal mortality between 2000 and 2020. However, maternal mortality rates remain high compared to most countries in the WHO Western Pacific Region, with an estimated 126 deaths per 100,000 live births in 2020. The major non-obstetric causes of maternal mortality were HIV and tuberculosis (TB) infections. Objectives: : To determine the proportion of HIV/TB testing and assess knowledge of HIV and TB among pregnant women attending antenatal care (ANC) at the Central hospitals, Vientiane provincial hospitals, and peri-urban district hospitals in Vientiane Capital. Methodology: : This cross-sectional study was conducted from July 2022 to December 2022. Four central hospitals and four district hospitals in Vientiane City and Vientiane Provincial Hospital were selected as study sites. Participants were interviewed face-to-face using a standardized questionnaire covering sociodemographic characteristics, obstetric history, ANC attendance, HIV/TB testing history, and knowledge of and attitudes towards HIV/AIDS and TB. Data were analyzed using STATA version 17. Univariate analysis, including frequencies and percentages, was used to describe variables and identify patterns. Factors associated with adequate knowledge of, and attitudes towards HIV and TB were assessed using multiple logistic regression analysis. Results: : Among 1,964 pregnant women attending ANC at the selected sites, the proportion of HIV-positive cases detected via rapid testing was 0.6%. None of the participants had been tested for TB. Misconceptions about HIV and TB were prevalent. For example, 35.7% of participants believed that HIV could be transmitted by sharing food with an infected person, and only 13.7% correctly identified TB as being caused by bacteria. Overall, 45.0% and 42.8% of participants had good knowledge of HIV and TB, respectively. Additionally, 25.9% pregnant women had a positive attitude towards HIV/AIDS, while 45.1% had a positive attitude towards TB. Factors significantly associated with knowledge of HIV/AIDS and TB included obstetric and ANC history, positive attitudes towards TB, and awareness of TB testing locations. Conclusion: The study highlighted a low prevalence of HIV/AIDS among pregnant women attending ANC at central and district hospitals in Vientiane Capital. However, knowledge of HIV/TB was limited, and attitudes towards HIV/TB were generally negative. These findings emphasize the need for targeted interventions, educational initiatives, and awareness campaigns to improve knowledge, correct misconceptions, and foster positive attitudes towards HIV/AIDS and TB among pregnant women. The insights from this study can inform the development of policies, programs, and preventive strategies aimed at reducing HIV/AIDS and TB infections.