In this study, using data from a prospective study of Korean patients with ACS, we identified significant interaction effects of diabetes with both the sBDNF level and BDNF Val66Met polymorphism on acute SI, in that the incidence of acute SI was significantly higher in the presence of diabetes and a low sBDNF level or the BDNF Met/Met genotype compared with higher BDNF levels and other genotypes. This evidence concerns the gene BDNF and diabetes mellitus.