| Merchant Marine Distinguished Service Medal | |
|---|---|
 Obverse and reverse of the medal | |
| Type | Individual Award |
| Awarded for | Outstanding conduct or service in the line of duty. |
| Presented by | United States Maritime Administration |
| Eligibility | Merchant Marine seamen |
| Established | April 11, 1942[1] |
| Total | 152 |
| Total awarded posthumously | 30 |
 Merchant Marine Distinguished Service Medal ribbon | |
| Precedence | |
| Next (lower) | Merchant Marine Meritorious Service Medal |
The Merchant Marine Distinguished Service Medal is a decoration of the United States Merchant Marine (USMM). The decoration is the highest award which can be bestowed upon members of that service. It is awarded to any seaman in the USMM who, on or after September 3, 1939, has distinguished himself during the war by outstanding conduct or service in the line of duty. Regulations state that not more than one medal shall be issued to any one seaman, but for each succeeding instance sufficient to justify the award of a medal, there will be awarded a suitable insignia to be worn with the medal.
As the Merchant Marine Distinguished Service Medal is considered a federal service decoration, it may be worn on the uniforms of active, reserve, and retired uniformed service members.