The United Nations Observer Mission in Sierra Leone shortly UNOMSIL (of English. United Nations Observer Mission in Sierra Leone ) took of 13 July 1998 to 22 October 1999. It was purely a military observation that the peace mission United Nations Mission in Sierra Leone (UNAMSIL).
The cost of this operation was US $ 12.9 million, but the UN Secretary General puts it at 40.7 million. In July 1998 70 military observers were authorized (effective 41 in November 1998) and increased to 210 in August 1999 (effective 192 plus 15 other military officers in October 1999). The observers were supported by 15 medical assistants, five civilian police officers and an administration of 30 international and 25 local employees.