I asked about it one time, even though I was pretty sure that I couldnt. I was told I had to weigh no less than 120 (which I didnt). I also read a paper that stated that if you had asthma you couldnt donate. I figured that if ppl with asthma couldn't donate, then I was pretty sure CFers couldnt, but I asked anyway, given I was actually the proper weight, and they told me no because of breathing problems.