Due to the observation of a great number of patients having achrocordons, when they underwent fine needle biopsies for thyroid nodules, we decided to perform a prospective study to investigate the relationship between this finding and the presence of insulin resistance (IR), since achrocordons are commonly seen in hyperinsulinemic subjects. A total of 120 consecutive women, aged 18-35 yrs were studied. All subjects were also evaluated by thyroid ultrasound (US) for measuring thyroid volume and the presence of non-palpable nodules. Basal and post-prandial serum insulin was measured in all of them, as well as the Homeostasis Model Assessment (HOMA). Subjects were divided in two groups: Group A, with achrocordons (n = 44) and Group B, without achrocordons (n = 76). Group A showed 24 patients (54.5%) with thyroid nodules, whereas Group B only 13 subjects (17.1%); p = 0.0087. When we considered, as having high normal thyroid volume, the glands weighting more than 16 grams by US, without nodules, it was found that 8/44 cases from Group A (18.6%) and 3/76 from Group B (3.9%) fitted in such category, p = 0.0076. In patients with nodules and/or bigger thyroids, IR was observed in 36/44 (81.8%) of Group A and 14/76 (18.4%) of Group B, p = 0.0069, while the overall prevalence of IR was 0.47 in Group A and 0.05 in Group B, p = 0.00094. It is concluded that patients with achrocordons have a higher prevalence of US-detected thyroid nodules and larger thyroid glands. Then, it may be beneficial to search for thyroid abnormalities in those subjects with skin tags.