Abstract Background Data regarding the relation between serum myostatin level, type I interferon-inducible gene expression and insulin resistance in dermatomyositis patients are limited. This study aimed to assess serum myostatin level, homeostatic model assessment of insulin resistance (HOMA-IR) and type I interferon-inducible gene expression in dermatomyositis patients. We evaluated the role of serum myostatin level, and type I interferon-inducible gene expression in the pathogenesis of dermatomyositis as well as the relation of serum myostatin level and type I interferon-inducible gene expression to the occurrence of insulin resistance. We evaluated serum levels of myostatin and HOMA-IR utilizing ELISA as well as IFIT1 and Mx1(MxA) gene expression with RT-PCR in 25 dermatomyositis patients (group A) and 25 obviously sound subjects as controls (group B). Results Among group A, body mass index, serum levels of myostatin, fasting insulin, HOMA-IR, IFN-inducible genes Mx1 and IFIT1 were more significantly increased as well as; serum level of myostatin was positively correlated with age, gender, fasting insulin level, body mass index, and HOMA-IR. Conclusions Serum level of myostatin, Mx1 and IFIT1 gene expression act as hazard factors of insulin resistance in group A.