Hb Davenport is a new, stable alpha chain variant, that was detected in two members of a Caucasian family living in Iowa. Hematological data were within normal limits. It is characterized by an Asn----His replacement at position alpha 78. Mild acidic hydrolysis of the large alpha T-9 peptide, separation of the resulting fragments by reversed phase high performance liquid chromatography, and sequence analysis of a few of these peptides greatly facilitated the identification of this substitution.