Romanian Catholics, like Catholics elsewhere, are members of the Catholic Church under the spiritual leadership of the Pope in Rome. The administration for the local Latin Church is centered in Bucharest, and comprises two archdioceses and four other dioceses. It is the second largest Romanian denomination after the Romanian Orthodox Church, and one of the 18 state-recognized religions. The 2022 census indicated that there were 741,504 Romanian citizens adhering to the Latin Church (3.89% of the population). Of these, the largest groups were Hungarians (54.7% or 405,212, including Székely and Csángó), Romanians (38.2% or 283,092), Germans (1.7% or 12,495) and Slovaks (0.9% or 6,853).

Most Romanian Latin Catholics inhabit the region of Transylvania and Bacău County in Moldavia. Smaller Latin Catholic communities exist among Banat Bulgarians, Italian-Romanians, Polish-Romanians, Croat-Romanians and Krashovani, Czech-Romanians and the local Romani people.

The Romanian Church United with Rome, Greek-Catholic is an Eastern Catholic sui iuris church which uses the Byzantine Rite. It has separate jurisdictions, five eparchies, and one archeparchy headed by a major archbishop (thus the church has its own synod), and has historically been strongest in Transylvania. The majority of its members are Romanians, with groups of Ukrainians from northern Romania. Members of the Armenian community who belong to the Armenian Catholic Church are organized in the Latin Church-led Ordinariate for Catholics of Armenian Rite in Romania. The Armenian Rite as used by its largely Transylvanian membership was significantly hybridized into the 20^th century.

The Archdiocese of Bucharest is the metropolitan see for the entire country's Latin jurisdiction, directly overseeing the regions of Muntenia, Northern Dobruja and Oltenia; it has around 52,000 parishioners, most of them Romanians. The other diocese of its rank, the Archdiocese of Alba Iulia (in Alba Iulia), groups the region of Transylvania-proper (without Maramureș and Crișana), and has around 480,000 mostly Hungarian parishioners. Four other dioceses function in Romania and are based, respectively, in Timișoara (the Diocese of Timișoara, representing the Banat), Oradea (the Diocese of Oradea, for Crișana), Satu Mare (the Diocese of Satu Mare, for Maramureș), and Iași (the Diocese of Iași, for Moldavia).

The church presently runs a faculty of theology (as part of the Babeș-Bolyai University in Cluj-Napoca), four theological institutes, six medical schools and sixteen seminaries (see Religious education in Romania). Among the journals issued by Catholic institutions are the Romanian-language Actualitatea Creștină (Bucharest) and Lumina Creștinului (Iași), as well as the Hungarian-language Keresztény Szó and Vasárnap (both in Cluj-Napoca). It leads a network of charitable organizations and other social ventures, administrated by its Caritas foundation or the religious institutes; it includes kindergartens, orphanages, social canteens, medical facilities.

The oldest traces of Catholic activities on present-day Romanian territory were recorded in Transylvania, in connection to the extension of Magyar rule and the region's integration into the Kingdom of Hungary (see History of Transylvania). Inaugurated by the early presence of Benedictines, these were strengthened by the colonization of Transylvanian Saxons, as well as by missionary activities among the local Vlach (Romanian) population and forceful conversions. The Diocese of Alba Iulia (Gyulafehérvár) was probably set up in the 11^th century. Tradition holds that this was done under supervision from King Stephen I — according to the Catholic Encyclopedia of 1913, a more likely patron is Ladislaus I, who ruled almost a century after (the first bishop it lists is Simon, who held the see between 1103 and 1113).

Other dioceses were created in Cenad (Csanád) and Oradea (Nagyvárad). They were subordinated to the Archbishop of Kalocsa, part of the Catholic Church in Hungary. The northern area comprised in the comitatus of Máramaros was originally part of the Alba Iulia Diocese, while the southern one, Szeben, was a provostship not comprised in any bishopric (and thus exempt).

During the rule of Béla IV, the Catholic hierarchy was disestablished by the Mongol incursion (see Battle of Mohi), and only recovered after 1300. In 1304, Pope Boniface VIII sent the first Catholic missionaries from Transylvania into the lands over the Carpathian Mountains (the area known as "Cumania"), where Eastern Orthodox bishops were already present. A Diocese of Cumania was created on the Milcov, in areas later ruled by Moldavia and Wallachia. Its assets were granted by the Hungarian rulers, whose claimed suzerainty over the region, and it extended over parts of Székely Land.