When the World Championship commenced in 1949 it was for both manufacturers and riders.

The manufacturers section was dropped at the end of 1953.

The first World champions in 1949 were:

Manufacture
125 Mondial
250 Guzzi
350 Velocette
500 A.J.S.
Sidecar Norton

Rider
125 N. Pagani
250 B. Ruffo
350 F. Frith
500 L. Graham
Sidecar E. Oliver