According to the 2011 census, 79.4% of the population was agnostic, atheist or irreligious (34.2% answered they had no religion and 45.2% didn't answer the question), 10.3% was Roman Catholic, 0.8% was Protestant (0.5% Czech Brethren and 0.4% Hussite), and 9.4% followed other forms of religion both denominational or not.

From 1991 to 2001 and further to 2011 the adherence to Roman Catholicism decreased from 39.0 to 26.8 and then to 10.3; Protestantism similarly declined from 3.7% to 2.1% and then to 0.8%.[85]

According to a Eurobarometer Poll in 2005, 19% of Czech citizens responded that "they believe there is a God" (the second lowest rate among European Union countries after Estonia with 16%), whereas 50% answered that "they believe there is some sort of spirit or life force" and 30% said that "they do not believe there is any sort of spirit, God or life force".