Apolipoprotein C-III (apoC-III) is involved in triglycerides metabolism, and is therefore important for the pathogenesis of coronary heart diseases. However, to our knowledge serum apoC-III variation factors and reference limits have never been determined, so the aim of this study was to establish them and facilitate clinical usefulness. We measured serum apoC-III concentration of apparently healthy subjects of the Stanislas Cohort by an immunoturbidimetric method. Genetic polymorphisms within the APOC3, APOE, APOAIV, and LPL genes were determined by a multiplex PCR. Serum apoC-III concentration varied from 28.2 mg/l to 225.8 mg/l in the overall sample and between subjects variability was about 30%. Factors influencing apoC-III concentration were age, BMI in adult men, alcohol consumption in adults, oral contraceptive intake in women, the post-pubescent status in boys. The APOC3 1100T allele in adult men and the APOC3 -455C allele in boys were associated with increased apoC-III concentration. The APOA4 360His allele was associated with decreased apoC-III concentration in women. We also established reference limits of serum apoC-III concentration according to age and gender.