Familial hypercholesterolemia (FH) has an estimated frequency of 1:154 among French Canadians in Northeastern Quebec, compared with 1:500 in most other populations. FH is caused by numerous mutations of the low-density lipoprotein (LDL) receptor gene, but only six well-characterized mutations are known to cause FH in French Canadians. High prevalence of the phenotype, along with a limited number of mutations in this population, provides a unique opportunity to study genotype-phenotype variation. Since the current methods for detection of point mutations in this population use complicated approaches, we report polymerase chain reaction (PCR)-based restriction fragment analysis to detect all four point mutations. This approach provides a rapid diagnosis and is suitable to screen large number of samples for studies in genetic epidemiology; it should be useful in identifying FH in other populations bearing the same mutations.