The study has been conducted with the objective of assessing the customer service quality of Tamilnad mercantile bank limited in Tirunelveli district. The use of core banking system is drastically changing the way of banking activities. Almost all banks are transforming their banking system to the modern technology in which they can offer efficient banking services to their customer and get customer satisfaction in return. Hence the researcher has taken the study entitled customer satisfaction of core banking services. 100 samples were selected by convenience sampling method. The study reveals that majority of the customers are satisfied with the core banking services provided by the Tamilnad mercantile bank limited in Tirunelveli district.

Key words; Core banking services, Tamilnad mercantile bank, Customer satisfaction.