An integral part of an enterprise computer security incident response team (CSIRT), the security operations center (SOC) is a centralized unit tasked with real-time monitoring and identification of security incidents. Security information and event management (SIEM) systems are an important tool used in SOCs; they collect security events from many diverse sources in enterprise networks, normalize the events to a common format, store the normalized events for forensic analysis, and correlate the events to identify malicious activities in real time. In this article, the authors discuss the critical role SIEM systems play SOCs, highlight the current operational challenges in effectively using SIEM systems, and describe future technical challenges that SIEM systems must overcome to remain relevant.