Steak qualities/beef grades in Canada? In his answer, @hobodave describes the three grades of beef available in the States: Select, Choice, and Prime. He further points out that most supermarkets only carry Select grade.

What are the grades available in Canada, and where can one find higher grades of beef?
The grades that you would be interested in, that are available in Canada, are:
Prime, AAA, AA, and A

See:
Beef Grades and Comparison with US Grades 

You can get Sterling Silver Beef in most grocery stores and it is either Prime or high quality AAA. It is also aged for 21 days. 

You can also order Prime on-line or ask your favourite butcher.