Every child has the right to a name and a nationality, as stipulated in the Convention on the Rights of the Child (CRC). Birth registration is a sure way of guaranteeing this fundamental right. Yet in Cameroon, 33.9% of children under the age of five are not registered. The regions of, Far North, South West, East, and North have the highest levels of non-registration, which are 57.9%; 44.4%; 41.8% and 39.1% respectively (MICS, 2014). With the aim of improving the state of knowledge of the explanatory factors of non-registration of births at the civil registry in these regions, the main objective of our work is to identify and prioritize the explanatory factors of non-registration of children aged 3 to 59 months in the East, Far North, North and South-West regions of Cameroon. To achieve this objective, data from the fifth Multiple Indicator Cluster Survey conducted in Cameroon in 2014 were used. Methodologically, descriptive analysis (chi-square test) and explanatory analysis (binomial logistic regression) were used.