The Marine Corps uses a four-digit MOS system. The first two digits designate the occupational field, and the last two digits identify the specific specialty within that field.

For example, 0311 is a Rifleman, where “03” represents the Infantry field and “11” identifies the specific job role.

Below are some of the main occupational fields in the Marine Corps. This is not a complete list. For the most up-to-date information, please visit the official U.S. Marine Corps website.