Introduction: One of the difficulties in dealing with tinnitus is its multiplicity of etiological diagnosis, which, in turn, may be associated in the same patient. A few studies have considered the association between tinnitus and alterations in the levels of glucose, lipids and thyroid hormones. Objective: to analyze the frequency of such alterations in tinnitus patients. Methods: From January 1995 to June 1999, 358 patients were evaluated by a standard medical-audiological protocol which included, among other items, fast glucose levels (or glucose tolerance test in specific cases), cholesterol, triglycerides and thyroid hormones, performed in the same laboratory. Results: Regarding the glucose metabolism: 15,7% showed higher levels of fast glucose (p=0,016) and 90,3% showed alterations in the glucose tolerance test. Regarding the lipids metabolism: the cholesterol levels were altered in 56,9% (p=0,003)and the triglycerides in 15,5%. Lastly, at least one alteration in the thyroid hormones was seen in 15%. Conclusions: such alterations are common in tinnitus patients, especially those regarding glucose and cholesterol levels. Thus, the otolaryngologist should include the evaluation of such medical problems in the routine investigation, referring the altered cases to a multidisciplinary team in order to reverse them and obtain better results in the tinnitus control.