i only know yellow is 100%
The tee's I bought were in colors and 100
The Tee's I bought were in colors and 100 % cotton. I think it depends on what's available at the time you're purchasing. I really like these Tee's. They are well made and very comfortable.
At least white, navy, and yellow
I think any moisture-wicking shirt has some non-cotton content. So there are no colors that are 100% Cotten. This is a little lighter weight and more breathable than Hanes other all-Cotton tees.