During the Inquisition of the 16th Century the Catholic Church burned at the stake hundreds of thousands of Spanish Jews, Muslims and Protestants. There was discrimination against non-Catholics under Franco, but the constitution of 1978 provided for equality of rights for all religions.

Over 90% of the population are nominally Roman Catholic, but 30% of those baptized are no longer affiliates, and as many as 50% are no longer active. Increasingly, atheism, materialism and cultic activity are filling the spiritual vacuum. Gambling is also a major problem.  

PCI partners with the Spanish Evangelical Church (IEE), a small denomination with around 3,000 members.