The 2004 World Thoroughbred Racehorse Rankings was the inaugural edition of the World Thoroughbred Racehorse Rankings. It is an assessment of racehorses which was issued by the International Federation of Horseracing Authorities (IFHA) in January 2005. It includes horses aged three or older which raced or were trained during 2004 in countries where the flat racing year runs from January 1 to December 31. These countries are generally in the Northern Hemisphere.