An asset register is a comprehensive, systematically maintained inventory that documents all valuable resources within an organization's IT and security infrastructure. This foundational document catalogs both tangible and intangible assets—including hardware devices, software applications, network components, data repositories, cloud services, and intellectual property. Each entry typically records critical attributes such as asset ownership, physical or virtual location, operational status, business criticality, associated security controls, and lifecycle stage.

In cybersecurity and risk management, an asset register serves as an essential tool for understanding an organization's complete attack surface and potential vulnerabilities. By maintaining accurate documentation of all assets, security teams can effectively identify and prioritize risks, conduct thorough vulnerability assessments, and develop targeted threat intelligence strategies. The register supports incident response planning by clarifying the potential impact of security breaches, ensures regulatory compliance, and enables informed decision-making for security resource allocation. As a living document, it requires continuous updates to reflect technological changes and organizational evolution.