"We will formalize in Brussels next week - and this is very important - Colombia's entry into NATO in the category of the global partner. We will be the only country in Latin America with this privilege," Santos said in a televised address.
Colombia joined the ranks of Afghanistan, Australia, Iraq, Japan, the Republic of Korea, Mongolia, New Zealand and Pakistan.
The announcement was made on the same day that the Organization for Economic Cooperation and Development (OECD) said that Colombia would be officially invited to join the group.
The Paris-based economic organization was founded in 1961 and has traditionally included industrialized nations, though in recent years it has extended its membership to emerging economies.
The North Atlantic Treaty Organization is an intergovernmental military alliance between 29 North American and European countries based on the North Atlantic Treaty that was signed on 4 April 1949.