['An important inter-individual variability in the response of insulin sensitivity following a fish oil supplementation has been observed. The objective was to examine the associations between single nucleotide polymorphisms (SNPs) within sterol regulatory element binding transcription factor 1 (SREBF1) gene and the response of insulin sensitivity to a fish oil supplementation.', 'Participants (n\u2009=\u2009210) were recruited in the greater Quebec City area and followed a 6-week fish oil supplementation protocol (5 g/day: 1.9-2.2 g EPA; 1.1 g DHA). Insulin sensitivity was assessed by the quantitative insulin sensitivity check index (QUICKI). Three tag SNPs (tSNPs) within SREBF1 gene were genotyped according to TAQMAN methodology.', 'Three tSNPs (rs12953299, rs4925118 and rs4925115) covered 100% of the known genetic variability within SREBF1 gene. None of the three tSNPs was associated with either baseline fasting insulin concentrations (rs12953299, rs4925118 and rs4925115) (p\u2009=\u20090.29, p\u2009=\u20090.20 and p\u2009=\u20090.70, respectively) or QUICKI (p\u2009=\u20090.20, p\u2009=\u20090.18 and p\u2009=\u20090.76, respectively). The three tSNPs (rs12953299, rs4925118 and rs4925115) were associated with differences in the response of plasma insulin levels (p\u2009=\u20090.01, p\u2009=\u20090.005 and p\u2009=\u20090.004, respectively) and rs12953299 as well as rs4925115 were associated with the insulin sensitivity response (p\u2009=\u20090.009 and p\u2009=\u20090.01, respectively) to the fish oil supplementation, independently of the effects of age, sex and BMI.'] Do sREBF1 gene variations modulate insulin sensitivity in response to a fish oil supplementation?