The number of people connecting to the cellular network is growing exponentially. They generate a massive amount of data that reveals the user's interaction patterns. By analyzing the data, the quality of experience of the customers of the cellular network can be improved. Big data analytics can process large amounts of raw data and extract useful insights from the analysis. In this paper, we use the call detail report (CDR) of the users in a specific area. The CDR dataset provides the information of a caller, called numbers, the duration of the call and the caller location. Using big data analytics tool, we could find any anomalous behavior in the cellular network over a region. Anomaly refers to any unusual behavior in the network. K-means clustering technique is used to detect anomalies in the network. The anomaly due to high data traffic at a location can be used to improve the network performance by adding additional resources. © 2018 IEEE.