Yes, the maximum length of an email address is 254 characters.
Every email address is composed of two parts. The local part comes before the '@' sign, and the domain part follows it. In "firstname.lastname@example.org", the local part is "user", and the domain part is "example.com".
- local part must not exceed 64 characters and
- the domain part cannot be longer than 255 characters;
- the total combined length of all characters (including '@' and punctuation) must not exceed 254 characters, however.
In sum, an email address can be 254 characters long at most. When you create an address, make sure your user name has less than 65 characters (provided the domain is 188 characters long at most).
(Updated August 2013)