The research presents a study on chillers performance at a gas district plant during peak and off peak periods for campus cooling. The plant is designed to produce electrical power and chilled water from a Co-generation System and supply the chilled water and electricity to the campus. Since the campus chilled water supply depends solely from the chillers operations, the status of the performance of the chillers need to be continuously evaluated. Using Coefficient of Performance (COP), the performances for both the absorption and electric chillers were analysed. This COP analysis is the follow up from the earlier evaluation which was done in the year 2005. Results of the analysis in&cate that there is a decrease in performance for the year 2011 in comparison to the year 2005. In terms of chilled water production the performance decreases approximately by 5. While in terms of coefficient of performance there is a decrease by 43 from the year 2005 for the absorption chillers and 32 increase for Electric the chillers. © 2013 Asian Network for Scientific Information.