By using cDNA probes for the human albumin gene, four restriction enzyme fragment length polymorphisms (RFLPs) were discovered that were transmitted by codominant autosomal inheritance. Among Caucasians, the gene frequencies were 0.04/0.96 for Msp I/5', 0.43/0.57 for Hae III/3', 0.44/0.56 for Hae III/5', and 0.04/0.42/0.54 for Pst I/5'. These common variants provide a marker for chromosome 4 (q11-q13). A calculation of the extent of DNA variation at the albumin locus revealed that 1/95 nucleotide sites was affected by a RFLP, a figure similar to that found in the globin system. Restriction enzyme fragment study of the DNA of a human analbuminemic individual revealed no gross structural rearrangements of the albumin locus. The exact nature of abnormality will require more study.