The body of a MIME message contains the actual content of the message. It is separated from the last header field by a blank line: a two-byte sequence consisting of an ASCII carriage return (CR) and an ASCII linefeed (LF) on a line by itself.

The message body can contain any sequence of data, including additional MIME messages. It is sometimes referred to as the payload. When you send an e-mail message, the body of your letter resides in the body of a MIME message. Similarly, when you attach a file to an e-mail message, the content of the file is carried in the body of a MIME message.