A complete civil registration and vital statistics system is the best source of data for measuring most of the Sustainable Development Goal 3 indicators. However, civil registration does not include migration data, which are necessary for calculating the actual number of people living in a given area and their characteristics such as age and sex. This information is needed to facilitate planning, for example, for school places, health care, infrastructure, etc. It is also needed as the denominator for the calculation of a range of health and socioeconomic indicators. Obtaining and using these data can be particularly beneficial for measuring and achieving universal health coverage (Target 3.8), because civil registration can help to identify persons in need of health care and enable decision-makers to plan for the delivery of essential services to all persons in the country, including the most disadvantaged populations. By assigning unique identification numbers to individuals, for example, at birth registration, then using these numbers to link the individuals’ data from civil registration, national identification, and other functional registers, including registers for migration and health care, more accurate and disaggregated population values can be obtained. This is also a key to improving the effectiveness of and access to social services such as education, health, social welfare, and financial services. When civil registration system in a country is linked with its national identification system, it benefits both the government and its citizens. For the government, having reliable and up-to-date vital events information on its citizens supports making informed program and policy decisions, ensuring the accurate use of funds and monitoring of development programs at all levels. For individuals, it makes it easier to prove one’s identity and the occurrence of vital events to claim public services such as survivor benefits or child grants.