Message-Driven Beans (MDBs) are a type of enterprise bean in the Java EE (Enterprise Edition) framework. They are designed to handle asynchronous messages from a messaging system, such as Java Message Service (JMS). MDBs allow applications to process messages without needing to manage the complexities of message handling directly. MDBs are typically used in scenarios where applications need to respond to events or messages, such as processing orders or notifications. They can be easily integrated with other components in a Java EE application, providing a scalable and efficient way to manage communication between different parts of the system.