This article examines the effect of access to health care center, in terms of travel time, on childhood immunization in Nepal using the 2004 and 2011 waves of the Nepal Living Standards Measurement Surveys. We employ probit and instrumental variable probit estimation methods to estimate the causal effect of travel time on the probability of immunization. Results indicate that travel time to the nearest health center displays a significant negative association with the probability of immunization (coefficient = -0.015, P < .05). Furthermore, the effect of travel time tends to be stronger in rural and distant areas of Nepal’s mountain and hill regions. The results suggest that policy interventions should increase the number of mobile clinics in rural villages and provide conditional cash transfer to incentivize immunization coverage at the household level. In addition, household income, parental education, ethnicity, and household location emerge as important determinants of immunization in Nepal.