OBJETIVE: To determine the incidence of Marine-Lenhart syndrome (MLS) in the previously thyroidectomies reported and describe its epidemiology, symptoms, diagnosis methods and compare with Plummer syndrome (PS). MATERIALS AND METHODS: Medical records of 694 hyperthyroid patients were reviewed and ANOVA was perform to compare age of patients, time of disease and thyroid's weight between MLS (diffuse hyperthyroidism with at least 1 node with increased uptake and with or without cold nodes) and PS. RESULTS: The MLS was reported in 4,3% of hyperthyroidisins and 1,2% of the total. Patients age, time of disease and thyroids weight were significantly different between MLS and PS. MLS produced pressure symptoms in two thirds of the patients and functional sings and symptoms in the most of them. In fotir of our patients we fotind exoplitalmos and orily one developed thyroid carcinoma. Total thyro...