Registration of birth within the first year of life is important to ensure children receive its full benefits and that fertility statistics derived from these data are informative for policy. This study provides an up-to-date global and regional assessment of the timing of birth registration by using all available birth registration data of children aged less than five years reported in Demographic and Health Surveys and Multiple Indicator Cluster Surveys from 2010 onwards. We calculated adjusted age-specific birth registration completeness by converting period age-specific completeness data into a hypothetical cohort. Timing of birth registration was analysed using ratios of adjusted age-specific completeness, with differentials by region, over time, and level of completeness assessed using bivariate and multivariate analyses. Almost 20% of registered births in countries with incomplete birth registration (less than 95%) were not registered until after 12 months, and this has not improved since 2010. In several countries this figure is greater than 50%, particularly in South Asia. There remains considerable scope to improve the timeliness of birth registration, particularly in countries where the overall level of completeness is lower. Strengthening and enforcing legislation for the mandatory registration of births before age 12 months and greater involvement of the health sector in registration processes are two ways which will improve birth registration timing.