摘要:Background In Tanzania only an estimated one-quarter of births are registered and certified. Birth registration uses a centralized system with geographic and cost barriers for families. A pilot decentralized birth registration system has been trialled in 11 of 26 regions, substantially increasing registration points, and enabling notification, registration and certification to occur in one step. Objective This study compares completeness of birth registration and certification and achievement of key birth registration milestones in two districts where the birth registration system decentralized and two districts with the existing centralized system. Methods Registration, notification, census and survey data were used to estimate birth registration completeness and quantify achievement of key registration milestones for births in 2012–16. These were compared between districts of Mbozi (decentralized in 2013) and Iringa (decentralized in 2016) and districts of Dodoma and Kibaha which remained centralized. Results For births that occurred from 2012 to 2016, completeness of birth registration/certification (by early 2017) was higher in districts that decentralized (Iringa 60%; Mbozi 52%) than remained centralized (Kibaha 36%; Dodoma 20%). Introduction of the decentralized system saw completeness for births registered within 12 months of occurrence increase in Iringa from 1% in 2014 to 67% in 2016, and in Mbozi from 15% in 2012 to 36% in 2013 before falling and subsequently increasing to 53% in 2016. In contrast, completeness in centralized districts did not increase. Although a higher proportion of births are notified in centralized than decentralized districts, registration and certification occurs for all notified births in decentralized districts but only one-third in centralized districts. Conclusions Benefits of a decentralized system are more proximate registration points and the merging of notification, registration and certification steps. The findings, while demonstrating the immediate impact of the decentralized system on completeness, also show that continued efforts are necessary to sustain these improvements.