AIMS--To present a non-isotopic procedure for the analysis of the different apolipoprotein E genotypes in normal subjects and patients with non-insulin dependent diabetes mellitus. METHODS--Apolipoprotein E genotypes were detected following polymerase chain reaction and miniaturised sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) (PhastSystem Pharmacia). RESULTS--The time taken from extraction of DNA from 6 microliters whole blood to the final result was eight hours. The allele frequencies in patients with diabetes mellitus in our series were similar to those found in the control subjects. CONCLUSIONS--SDS-PAGE is rapid, reliable and safe with few drawbacks, can be used as a routine procedure and may easily replace apolipoprotein E phenotyping.