Amplification of DNA recovered from a dried blood spot was used to genotype individuals with sickle cell disease, sickle cell carriers, and controls. A single 200-microliters blood spot applied to a filter paper provides sufficient material for more than 20 genetic analyses. In addition, the stability of the DNA is such that adequate material for amplification can be isolated from dried blood spots up to a year following collection. The DNA analysis methods described in this study could be applied to large-scale screening of newborns for genetic disorders.