The two major religions in Eritrea are Christianity and Islam. However, the number of adherents of each faith is subject to debate. Estimates of the Christian share of the population range from 47% and 63%, while estimates of the Muslim share of the population range from 37% to 52%.

They are 96% Christians, (of which 90% are of the Eritrean Orthodox faith, 5% Roman Catholic and Eastern Catholic (whose mass is held in Ge'ez as opposed to Latin), and 5% belonging to various Protestant and other Christian denominations, the majority of which belong to the (Lutheran) Evangelical Church of Eritrea).

The population of Eritrea is equally divided between Christian (Orthodox Church, Roman Catholic and Lutheran protestants) and Muslim religions. The population of the high plateau (Asmara) is predominantly Christian, whereas that of the lowlands and the coast are predominantly Muslim.

There are no reliable figures on religious affiliation. The Pew Foundation in 2016 estimated the population to be 63 percent Christian and 37 percent Muslim. Some government, religious, and international sources estimate the population to be 49 percent Christian and 49 percent Sunni Muslim.