Just to start with, the materials designation is different.
AWS refer to materials standardized by ASTM. ASTM A-6, for example, includes a broad list of steels used for structural purposes.
DIN St 37, for example, is a widely used material for structural applications. St means "stahl" (steel) and 37 means that the minimum yield point is 37 kgf/square millimeters (roughly 3,700 bars).
Another difference is the electrode designation. AWS has its own designation whereas DIN follows ISO's one.
I let the specialists to tell you other differences.
Giovanni s. Crisi
Sao Paulo - Brazil

Another thing to watch for on European drawings is that the size of a fillet weld refers to the throat size, not the leg size as we use in North America.

I have Din codes
my contry is holland europa