The number of Roman Catholics in Latin America, a historical stronghold, dropped to 67 percent in 2013, from 80 percent in 1995, a survey by Chile-based pollster Latinobarometro showed on Wednesday.
"In the recent data we don't see an impact in the number of Catholics following the arrival of Pope Francis at the head of the Church," Latinobarometro said, but added it was still too early to fully gauge the impact of the Argentine Pope elected in March of last year.
Still, it appears the former Archbishop of Buenos Aires is shoring up confidence in his flock.
Around 78 percent of Catholic Latin Americans said they trusted the Church last year, up from 69 percent in 2011, although the jump in confidence for Evangelical Christians was even higher.
The Church's child sex-abuse scandals and a perception that it is out of touch with today's concerns has opened the door to a rise in Evangelicalism, especially among the region's poor and in Central America.
Emotional, vibrant sermons at Evangelical churches, in contrast to the often solemn Catholic Mass, have also attracted believers.
In the regional powerhouse Brazil, for instance, roughly one in five self-identified as Evangelical Christians.
"Latin Americans embrace another religion when they abandon Catholicism," Latinobarometro said.
The exceptions are Chile and Uruguay, widely seen as the region's most stable and wealthy countries, where secularism is gaining ground.