BackgroundInsulin resistance is a common manifestation among patients with chronic hepatitis C. The aim of this study was to investigate the effect of haplotypes in the microsomal triglyceride transfer protein (MTTP) gene on insulin resistance in Brazilian patients with chronic hepatitis C. MethodsGenetic variants in the MTTP gene were genotyped by PCR-RFLP.Results: Of the 232 patients with chronic hepatitis C, 34.5 % had insulin resistance (HOMA-IR ≥3) and the majority were ≥50 years old. The minor allele frequencies for the -400A/T (rs1800803), -164T/C (rs1800804), H297Q (rs2306985), I128T (rs3816873), Q95H (rs61733139), Q244E (rs17599091) and -493G/T (rs1800591) variants in the MTTP gene were 0.41, 0.30, 0.49, 0.30, 0.08, 0.06 and 0.32. In multivariate analysis, elevated levels of gamma-glutamyl transpeptidase (GGT) was associated with insulin resistance (p = 0.006). Haplotype-based association testing presented that the haplotype ATCTGGG of the -400A/T, -164T/C, H297Q, I128T, Q95H, Q244E and -493G/T variants was associated with the presence of insulin resistance (p = 0.028) and the haplotype TTGTGCG may be a protective factor (p = 0.012). ConclusionThe combination of alleles in the -400A/T, -164T/C, H297Q, I128T, Q95H, Q244E and -493G/T genetic variants in the MTTP gene may play a relevant role in insulin resistance among patients with chronic hepatitis C.