The purpose of this research article is to evaluate the customers’ delight towards the service excellence in IOB in Chennai, Tamil Nadu. The researcher conducted a literature search on banking services of IOB interviewing of its 100 customers and thoroughly scrutinized how it caters to the banking needs of the inhabitants of IOB in Chennai Tamil Nadu. The study also focused on various factors that determine the customers’ satisfaction like employees’ behaviour, banking services, banking performance, infra- structure facility and other value added services. Analysis was made by using various tools like percentage Analysis. It is evident from the present study that a majority of the customers are highly satisfied with the banking services. This study is based on the primary data. Non-Random Sampling has been used for the collection of data. Collected data’s are analyzed through percentage analysis, Chi Square, Correlation and weighted average. After the analysis findings and suggestions were included in this article. From the final analysis it has been concluded that in IOB, it was found that the customers are satisfied with the services.