We have used a common TaqI restriction fragment length polymorphism (RFLP) near the human apolipoprotein C-II (apoC-II) gene to study linkage with apolipoprotein E (apoE). The inheritance of the apoC-II RFLP was followed in seven families that were segregating for apoE protein variants. No recombinants were observed in 20 informative meioses, giving an overall lod score of greater than 4.0 at recombination fraction 0. We have also observed apparent linkage disequilibrium between apoE and the apoC-II RFLP. Taken together these results demonstrate that these two apolipoprotein genes are closely linked and confirm that the gene for apoC-II is on human chromosome 19.