The 21st Century is witnessing a massive flow of information in library. The increasing amount of information can be related to the extensive application of Information & Communication Technology. Today, one of the biggest challenges that libraries face is the enormous amount of data generation and to use this data to improve the quality of managerial decisions. Data mining techniques are analytical tools that can be used to extract meaningful knowledge from large data sets. To do this extraction, data mining combines artificial intelligence, statistical analysis and database management systems to attempt to pull knowledge form stored data. The present paper addresses the applications of data mining in library in an effective and efficient manner.