CLR is .NET equivalent of Java Virtual Machine (JVM). It is the runtime that converts a MSIL code into the host machine language code, which is then executed appropriately. The CLR is the execution engine for .NET Framework applications. It provides a number of services, including:

- Code management (loading and execution)

- Application memory isolation

- Verification of type safety

- Conversion of IL to native code.

- Access to metadata (enhanced type information)

- Managing memory for managed objects

- Enforcement of code access security

- Exception handling, including cross-language exceptions

- Interoperation between managed code, COM objects, and pre-existing DLL's (unmanaged code and data)

- Automation of object layout

- Support for developer services (profiling, debugging, and so on)