The Live Birth Information System (SINASC) was implemented in 1990 for the purpose of providing information about the live-birth characteristics for the establishment of specific health indicators. This work evaluates the information quality of SINASC in relation to its data completeness and coverage for five municipalities from the State of Acre from 2005 to 2010. Lack of information (not filled out or stated as "unknown") was estimated for each variable. Coverage was estimated comparing the Civil Register office statistics in accordance with the mother's municipality of residence. An increase in incompleteness of the majority of variables was observed, and also a decrease in coverage between 2005 and 2010 in these municipalities. These findings do not tally with results from the majority of studies that use SINASC as a data source. The results of this work highlight the relevance of continuous capacity building and the incentive for accurate and complete data inclusion, as well as awareness of the importance of SINASC for public health policies.