Prior to the 1990s, there were two groups of the midget wrestlers, each of which had its own world title. The midget wrestling was usually for a comedy purpose, and most likely, its "championships" were not actual titles. The pre-1990s portion of this list only shows who held title at certain point in time but is not to provide any actual lineage(s).
Sky Low Low #
Wins 30-man tournament to become the first
World Midgets' champion; may not be recognized by NWA.
Little Beaver *
Sonny Boy Cassidy
Have been recognized as champion by non-NWA promoter in Dallas, TX as of 53/06; recognized in Memphis, TN as of 57/09 and Florence, AL as of 57/10.
Sonny Boy Cassidy 
Recognized as champion in Georgia.
Sky Low Low
El Paso, TX
Recognized in St. Joseoph, MO; still champion as of 69/01/31.
Recognized in Los Angeles, CA as of 72.
Also defends on 74/07/05 in Calgary.
Calgary, AB, CAN
Dallas , TX
Vancouver, BC, CAN
Billed as NWA champion on on an AWA card on 85/09/28 in Chicago, IL.