United Bank of India (UBI) is one of the 14 major banks which were nationalized on July 19, 1969. Its predecessor the United Bank of India Ltd. was formed in 1950 with the amalgamation of four banks viz. Comilla Banking Corporation Ltd.(1914), Bengal Central Bank Ltd.(1918), Comilla Union Bank Ltd.(1922) and Hooghly Bank Ltd.(1932) (which were established in the years indicated in brackets after the names). The origin of the Bank thus goes back as far as 1914. As against 174 branches, Rs.147 crore of deposits and Rs.112 crore of advances at the time of nationalization in July,1969, today the Bank has 1729 branches, over Rs.100745 crore of deposits and Rs.70402 crore of gross advances, as on 31.03.2013. Presently the Bank has a three-tier organizational set up consisting of the Head Office, 34 Regional Offices and 1729 branches.

After nationalization, the Bank expanded its branch network in a big way and actively participated in the development activities, particularly in the rural and semi-urban areas in conformity with the objectives of nationalization. In recognition of the role played by the Bank, it was designated as Lead Bank in several districts and at present it is the Lead Bank in 34 districts in the States of West Bengal, Assam, Manipur and Tripura. The Bank is also the Convener of the State Level Bankers’ Committees(SLBC) for the State of West Bengal and Tripura.

UBI played a significant role in the spread of banking services in different parts of the country, more particularly in Eastern and North-Eastern India. UBI has sponsored 4 Regional Rural Banks (RRB) one each in West Bengal, Assam, Manipur and Tripura. These four RRBs together have over 1000 branches. United Bank of India has contributed 35% of the share capital/ additional capital to all the four RRBs in four different states. In its efforts to provide banking services to the people living in the not easily accessible areas of the Sunderbans in West Bengal, UBI had established two floating mobile branches on motor launches which moved from island to island on different days of the week. The floating mobile branches were discontinued with the opening of full-fledged branches at the centres, which were being served by the floating mobile branches. UBI is also known as the 'Tea Bank' because of its age-old association with the financing of tea gardens. It has been the largest lender to the tea industry.

The Bank has three full fledged Overseas Branches and corporate business branches one each at Kolkata, New Delhi and Mumbai with fully equipped dealing room and SWIFT terminal. The operations of all the Branches have been Core Banking solutions under coverage of  Electronic Fund Transfer System. The Bank has 508 nos of ATMs all over the country.

The name of the RRBs, the location of the Head Office and the name of the present Chairmen are given in the following table