Can I hang pegboard on my cement block wall without studs?

Assuming it is the board I think it is, how will you put the hangers into it, if all of the back of the board is flat against the blocks.

Its metal and is offset to give enough space. Thanks.

Yes you can but proper mounting spacers are needed and also an adequate molly for cement block. Concrete Anchors - Wall Anchors (http://www.instockfasteners.com/PRODUCTS/concreteanchors.ASP)