Performance management system has generally been prominent as a tool that would help in enhancing the performance of both individual and organisation. This justified the need to carry out this research in titled challenges faced and the best practices in implementation of performance management system in Indian IT industry with a case study approach on Cognizant. The main objectives of this study are to understand the evolution of PMS and to explore the techniques followed in PMS, to identify the challenges faced by the managers, and to explore the best practices in PMS. To meet these objectives, in-depth information from the managers regarding their performance management system was required and thus interviews were conducted with four managers from the chosen organisation. The research found that the performance management system was not efficient and thus the organisation was facing some issues like employee dissatisfaction, lack of training and high attrition rate. It was also found that the managers were interested to drop rating system like Deloitte and Accenture to weekly check-ins but require support and directions from the management to implement them. So, it was recommended that the management rethinks about their performance management system before it becomes a disaster and bring in few changes like training for managers to manage conflicts and give constructive and continuous feedback, more intrinsic rewards based on performance of the human resources. Also, the organisation needs to understand that the workforce of a company is their most powerful resource and management needs to take steps to keep them motivated and increase performance by all means to achieve competitive advantage.