The Holy Trinity Orthodox Cathedral is the largest church in Arad, a large Byzantine-Romanian Revival building completed in 1939 in the northern part of the city centre. Its exterior combines Byzantine domes with Romanian folk decorative elements — a style developed in the early 20th century to express a specifically Romanian Orthodox identity distinct from both Habsburg Catholicism and Greek-influenced Orthodoxy.
The interior is richly painted with frescoes covering walls, vaults, and dome in the tradition of Romanian church painting. The cathedral serves as the seat of the Diocese of Arad and is active, so visits should be arranged to avoid disrupting services. The surrounding neighbourhood has several other churches — Arad has a significant Romanian Orthodox, Roman Catholic, Serbian Orthodox, and Reformed community, each with its own historic buildings.