From 1937 through 1946, México issued a national series of uniform license plates, marking a sharp departure from past practices.   

While we don’t know for sure when the first Mexican license plates were issued, we know the earliest survivors from about 1920 onwards came in all shapes, sizes, colors, compositions, and designs by municipality or state. 

Then in 1933, Mexico introduced the first national standards for license plate design, with all states, territories, and districts using the same size, colors, fonts and layout.  The state name was spelled out in full at the bottom  with all states along with the year. Tabs were used for 1934 and a similar base plate appeared in 1936 and 1936.

But 1937 everything changed. Now, there was a simple design used throughout the country, with no local distinction.  Further, we don’t believe there were any number blocks assigned to different states either.  “Mexico” and the year appeared embossed at the bottom, This design lasted three years, 1937-1939.  

The use of a national system continued in 1940 through 1946, with one important new addition: a state letter prefix used on passenger plates.  Non-passenger plates used different colors but had no state prefix; the same for dealer plates. 

By 1947, the short-lived national series was gone for good.  Using a standard design and format moving forward, plates were issued by state name from 1947 through 1998.  Starting in 1998, the new era of individual state graphics and colors arrived and the world of Mexican license plates became a very different and more colorful place. 

The 1937-1946 national series is notable because each year there were subtle variations:  1937-1939 where the same oversized plates, but different dies were used in 1937 and clipped corners in 1939.   The 1940-46 era saw design variations too–a debossed rectangle in 1943 similar to the USA’s Massachusetts 1947-1964 issues (perhaps Massachusetts copied Mexico?)   The 1945 plate had a debossed rectangular shield in the center of the plates.   Is anyone aware of any allocations of number series by state during this national period?