PURPOSE: Vaccination is one of the most effective and efficient health interventions for reducing morbidity and mortality from infectious diseases, particularly in sub-Saharan Africa. Understanding the determinants of access to vaccines can help improve immunization coverage and control vaccine-preventable diseases. The aim of this study was to explore the contribution of certain determinants to access to pentavalent 3 in children aged 0-23 months in Cameroon via demographic and health survey data. MATERIALS AND METHODS: This was a cross-sectional nested case‒control study in which children aged 0-23 months were selected via cluster random sampling in households in the 10 regions of Cameroon. Secondary data from the Demographic and Health Survey, which was conducted in Cameroon from 2017-2018, were used. Univariate and multivariate logistic models were used to analyze the determinants of access to the pentavalent 3 vaccine. RESULTS: The vaccination coverage of the pentavalent 3 vaccine (P3V) among children aged 0-23 months was 69.5%. The access to the P3V with Christian religion, compared with non-Christian experienced 63% of P3V (adjusted Odds ratio (AOR)=1.63, 95% CI, [1.22-2.17], p=0.001). Compared with those living in other regions in Cameron, those living in the northern regions of Cameroon were observed 37% less likely to have access to P3V (AOR=AOR=0.63, 95% CI, [0.44-0.87], p=0.006), while mother's marital status (married) compared with unmarried mothers were 37% more likely to experience access to P3V (AOR=1.37, 95% CI, [1.04-1.81], p=0.024). Relative to subjects with less education, those with at least secondary or higher education were 92% more likely to have access to P3V, (AOR=1.92, 95% CI [1.47-2.51], p<
0.001), while those with cell phone experienced 44% increased access to P3V, (AOR=1.44, 95% CI, [1.17-1.78], p=0.001). CONCLUSION: Access to the pentavalent 3 vaccine in Cameroon does not meet national targets and is affected by various socio-demographic factors, including region of residence, religion, educational attainment, maternal marital status, and cell phone ownership.