Data mining is an automated tool that uses multiple advanced computational techniques to identify significant and recognizable patterns, trends, and relationships. This type of information is useful to help predict future behaviors or events. The article describes why data mining technology is useful to law enforcement agencies that increasingly handle large amounts of information. Its usefulness is underscored for a variety of law enforcement functions such as tactical crime analysis, deployment, risk assessment, behavioral analysis, DNA analysis, Homeland security, and infrastructure protection. For example, when DNA evidence links a new perpetrator to an old case, data mining can be used to quickly and efficiently search all old case files to identify other crimes for which the same perpetrator may be responsible. Data mining is not only a useful analytical tool, it is also becoming more accessible as the current data mining software is user-friendly, personal-computer based, and affordable. Data mining is a flexible technique that can be used to extract meaningful data not only from statistical information, but from narrative information and from datasets that originate from different sources. After a description of the many uses of data mining, the authors stress the importance of adopting new analytical techniques to keep up with the ever increasing flow of information into law enforcement agencies. Endnotes