45 countries haven't taken part in the Olympic.
148 countries have taken part in the olympics
100
104012
205 countries
204 countries
There are 204 nations, countries, or National Olympic Committees as they are called
There are 205 countries participating in the 2012 Olympics.
204 (estimated).
A total of 11099 athletes from 202 countries and regions across the world took part in the 28th Olympics.
Around 10,500 athletes from 204 National Olympic Committees (NOCs) or countries took part in the 2012 London Olympics
Australia, France, Great Britain, Greece and Switzerland have competed in all of the Olympic games as of 2012.