Romania does not have a state religion (according to Article 29 (5) of the Romanian Constitution, religious cults are autonomous to the state). According to the 2011 census, 16,307,004 citizens, representing 86.45% of the population, declared themselves as Orthodox, 870,774 declared Roman Catholic (4.62% of the population), 600.932 reformed (3.19%), 362,314 Pentecostals (1,92%), 150,593 Greek Catholics (0,8%), 112,850 Baptists (0,6%), and so on In Dobrudja there is an Islamic minority (0.34%), composed mostly of Turks and Tartars. There are also a small number of atheists (0.11%), agnostics, people who are unreligious (0.1%) and people without a declared religion. According to Annuario Pontificio, the official census of the Vatican, during the same period, the internal census of the Catholic Church numbered 1,193,806 Roman Catholic believers (with 165,405 persons more than those recorded by the Romanian authorities).
According to a world study, “Religiosity and Atheism Index” by Gallup International, Romania is among the top 10 most religious countries in the world. Thus, Romania ranks 7th in the world, 89% of the population declaring that it is religious, being the only country in the European Union that appears in the top 10. The report also shows that Romania is among the few countries where the number of believers increased from 2005 until in 2012, from 85% to 89% of people declaring themselves religious.
In Romania, there are 18,436 places of worship in the year 2015. Of these, 14,765 are churches, 359 chapels, 1,096 prayer houses, 47 cathedrals, 2 bishops, 2 mosques, 76 glaciers, 286 monasteries and 89 synagogues. On average, there are 90 new churches in Romania, and these are only those of the Orthodox. Since 1989, until now, the Orthodox churches have multiplied by approximately 2,000 places of worship throughout the country.
The Great Mosque in Constanţa, also known as the Mosque of Carol, is a Muslim cult site in Constanţa, an architectural monument built between 1910 and 1913.
There were 18 religions and religious cults in the 2011 census.  The predominant is the Orthodox (16,307,004 of 20,121,641 people), followed by the Roman Catholic (870,774).
From the 7th century until the middle of the 11th century, still in the way of the migratory peoples, the Romanian people, although Christian from Roman times, still do not have the opportunity to consolidate their state existence and cultural affirmation.
The expansion of the Hungarians in Transylvania and the waves of the last barbaric invasions – of the Pechenegians, the Cumanians and the Tartars, created obstacles to the establishment of the Romanian state formations.
Romanian spirituality was greatly influenced by its strong ties to the Orthodox Christian – Greek and Orthodox Christian world. The Romanians have a unique sense of identity that they can express two distinct features: they are an island of Latinity in a great glory, as well as the only Latin country of Christian-Orthodox confession. There is also an important minority of Roman Catholics (both Roman and especially united rites) as well as communities of Protestant Romanians, especially those belonging to neo-Protestant churches such as the Pentecostal, Baptist, Adventist, Christian Gospel, etc. In contrast, the vast majority of Romanians are Orthodox (over 90%).
Romanian Orthodox monasteries and churches exist throughout Romania, but traditionally only a few are built on a monumental scale. A large number of wooden churches are still intact in the villages of the Carpathian Mountains, but by far the most impressive are the Wooden Churches of Maramureş, which pushes the wood technique of construction of its limits.
Byzantine influences can be found in most buildings, but the styles of Romanian churches have evolved over time and in different regions.
In the north of Moldova a certain style was used to build monasteries, of which the most important monasteries are from Bucovina – Places of UNESCO World Heritage, such as Moldovita, Putna, Sucevita, and Voronet.
In Muntenia Curtea de Arges Cathedral is built in Byzantine style, with Moorish influences, and a large number of churches have Greek influences, especially those built in the 18th century, such as the Stavropoleos Church in the center of Bucharest. In Romania, the Brâncoveanu distinctive style also evolved: the monasteries of Snagov and Sâmbăta de Sus, in Transylvania, are classical examples.