I donated through the Mother's Milk Bank in Austin, TX. It was really good experience and helped me stick with breastfeeding despite problems related to HUGE over supply. I'm not familar with the National Milk Bank. For the Austin bank I was required to fill out some forms, make an intial donation of 100 oz, and get lab work done (to check for hepitius, etc.). They milk bank payed for the lab work. My son's pediatrican also had to sign off on a form that he was healthy and not having feeding problems.