States of hyperinsulinemia with insulin resistance are frequently associated with proliferative tissue abnormalities, via stimulation of DNA synthesis and cell proliferation through the IGF-1 receptor. Such elements of metabolic syndrome (hyperinsulinemia/insulin-resistance, obesity, type 2 diabetes mellitus, hypertension, dyslipidemia) are explored in a population of 125 women (n. 50 with histologically confirmed diagnosis of breast cancer, Group A; n. 50 with benign breast pathology, Group B; n. 25 with no breast pathology, Group C, controls), affering to a Center for the prevention of breast cancer, in order to investigate for an eventual relationship between these pathologies. The prevalence of type 2 diabetes mellitus, hypertension, dyslipidemia, was higher in group of women affected by breast cancer vs. benign breast pathology and controls. This finding is in agreement with the hypothesis of the interrelationship of hyperinsulinism/insulin resistance with the growth-related abnormalities of breast cancer.