Allele frequencies of the AmpFLP system APO B were determined in an Austrian population sample consisting of 210 unrelated Caucasian individuals living in the Salzburg region. A total of 25 different alleles could be observed. The allele distributions were in accordance with Hardy-Weinberg equilibrium. No new mutations were found in 184 meioses and seven "interalleles" and four alleles < 29 could be detected.