The Knowledge Resource Center, CSIR-National Environmental Engineering Research Institute, Nagpur switching over from LIBSYS 7 to KOHA 3 - Integrated Library Management Software via open source software technology. Propose of this paper is to describe how to CSIR-NEERI implement and what are the steps taken to implement KOHA ILMS in the CSIR-NEERI KRC. The Migration of different data types, processing and depositing the same in KOHA system is also discussed. The use of Open Source Software in libraries is an increasing trend. OSS tools and implementations provide library institutions with access to a dynamic and cost effective solution for servicing user groups, manipulating large volumes of content, and facilitating communications between various institutional and public entities. Experience and conclusions from this installation might influence decisions at other libraries.