The increased strength of students make it difficult for librarian to keep an eye on each and everything. The computerized library management systems have increased efficiency compared to the traditional manual system. However, these computerized system are lacking in provision of security along with ease in management, especially in large and multi-story libraries. There is no security for library items and also no theft detection mechanism exist. If someone try to steal a library item, he can easily do that. Radio Frequency Identification (RFID) is a new generation of auto identification and data collection technology which helps to automate business processes and allows identification of large number of tagged objects like library items, using radio waves. Proposed system is based on RFID tags and RFID readers, supported with antennas at gate and transaction sections. The library cards contains QR code which are able to electronically store information that can be read / written even without the physical contact with the item. Books containing bar code and RFID tag can be scanned easily using bar code scanner. Efficient transactions can be made easily using this technology. RFID based Library Security system (LSS) would allow fast transaction flow, which will give long term benefits to library in traceability and security. It will ensure the security, management and theft detection for library items using RFID technology.