The aim of this paper is to explore the use and applications of Knowledge Management (KM) for improving Library and Information Services (LIS) in Bangladesh. This paper seeks to address the following research questions: How KM can be used efficiently in the libraries of Bangladesh for the improvement of LIS performance? What KM tools and techniques are being used in the libraries of Bangladesh? What difficulties are faced by the information professionals for applying KM tools and techniques in the libraries of Bangladesh? What are likely to be the means or ways to overcome those difficulties? The methodology includes a combination of both quantitative and qualitative approaches. An in-depth interview method has been used to collect data using a semi-structured questionnaire consisting of open-ended and close-ended questions. The results of this study show that document management is the highly used KM tool used in the libraries of Bangladesh followed by intranet, telephones, instant messenger, groupware, digital warehouse, and web conferencing. Results also reveal that the use and application of KM in LIS supports improved access to information resources and services, enriched professional knowledge of information professionals, enhanced environment and culture of knowledge sharing, and changed work behaviour of information professionals. The study identifies that lack of awareness about KM, lack of skilled manpower, communication gap and lack of knowledge sharing, and lack of technological infrastructure are the main problems for the use and application of KM. Finally, this study suggests that creating awareness about KM, trained and skilled manpower, reducing communication gap and improved knowledge sharing, technological and knowledge infrastructure, and the use of KM system/tools are the possible ways to overcome the problems for the use and application of KM in the libraries of Bangladesh.