Is MCO 5110.4B current?

MCO 5110.4B is listed as current in the MCPEL catalog (publication date 2021-12-09).

Where do I download the official MCO 5110.4B?

The official copy is published on MCPEL (https://www.marines.mil/News/Publications/MCPEL/).

MCO 5110.4B — MARINE CORPS POSTAL AFFAIRS AND OFFICIAL MAIL PROGRAM

MCO 5110.4B is listed as current Current
in the MCPEL catalog as of our last index refresh (2026-07-11).

Branch	U.S. Marine Corps
Series	MCO
Publication date	2021-12-09 (4.6 years ago)
Status	Current
Proponent / OPR	Not listed
Source of record	MCPEL

Official document (MCPEL)

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Get an email if MCO 5110.4B is revised, superseded, or rescinded.

Nearby in the MCO series

MCO 5104.1_ — NAVY LASER HAZARDS CONTROL PROGRAM Current
MCO 5104.2 — MARINE CORPS RADIATION SAFETY PROGRAM FOR DEPLETED URANIUM AMMUNITION Current
MCO 5110.1_ — MOTOR VEHICLE TRAFFIC SUPERVISION Current
MCO 5200.17F — STANDARDIZATION OF MILITARY AND ASSOCIATED TERMINOLOGY Current
MCO 5200.24F — MARINE CORPS’ RISK MANAGEMENT AND INTERNAL CONTROL PROGRAM Current

This is an unofficial index built from the public catalog. The controlling copy is always the one on MCPEL — verify there before citing MCO 5110.4B in an official product.