The soldier died from wounds received as a result of small arms fire which occurred near Sangin, in Helmand province, during the morning of Saturday 6 March 2010.
The soldier's death was not connected to Operation MOSHTARAK.
Spokesman for Task Force Helmand, Lieutenant Colonel David Wakefield, said:
"It is with deep sadness I have to inform you that a British soldier from 3 RIFLES lost his life this morning as a result of small arms fire.
"He was on a deliberate operation against insurgents to the south of Sangin district centre, near Patrol Base Suffolk, when he was shot.
"He died boldly taking the fight to the enemy and will not be forgotten."
The soldier's next of kin have been informed and have asked for a period of grace before further details are released.