Heritability studies have estimated the genetically attributable part of body mass index variance to be in the range of 30-70 %. Rs7566650 (G>C) single-nucleotide polymorphism (SNP) near the promoter of the INSIG2 gene has been identified as associated with body mass index. The gene product of INSIG2 is involved in regulation of fatty acid and cholesterol synthesis. In order to replicate this association we have analysed 2,559 unrelated individuals of Slavonic Caucasian origin from the populationbased Czech MONICA 3-year cohort. Body mass index, waist-hip ratio and plasma lipids (total-cholesterol, HDL-cholesterol, triglycerides) were measured at two independent examinations within three years. We could not detect any association between the SNP rs7566605 and body mass index, waist-hip ratio or lipid parameters, both with or without adjusting for age and gender. Neither the body mass index change nor lipid changes were significantly affected by the INSIG2 gene variant. Our results indicated that this INSIG2 polymorphism has no significant effect on body mass index and plasma lipids in the Czech Slavonic population.