Sending a message to an object results in performing some action; that is, it results in running some underlying code. The action-generating code is called a method. When you send a message to an object, you specify its method name in the message. Method names are character strings like REVERSE. In the preceding example, sending the reverse message to the !iH object causes it to run the REVERSE method. Most objects are capable of more than one action, and so have a number of available methods.

The classes Rexx provides include their own predefined methods. The Message class, for example, has the COMPLETED, INIT, NOTIFY, RESULT, SEND, and START methods. When you create your own classes, you can write new methods for them in Rexx code. Much of the object programming in Rexx is writing the code for the methods you create.