Background <p>Tinnitus is the ringing sensation in the ear in the absence of any external stimuli.The cause of tinnitus is not clearly known. Some suggests that there is a role of diet, nutrition in tinnitus. Thus in this study we evaluated serum magnesium levels in idiopathic tinnitus patients.</p> Materials and methods <p>A case control study was done with cases being bilateral subjective tinnitus without hearing loss and controls being patients with other illness. 30 patients were included in each group. THI questionnaire was given to cases and serum magnesium levels were measured and compared between the groups.</p> Results <p>The mean age in cases and controls were 32.7 years and 34.6 years respectively. The mean of total THI score of male and female in cases were 49 ± 15.5 and 50 ± 24.3 respectively. There was no significant difference between serum magnesium levels between cases and controls The grades of tinnitus and serum magnesium levels were also not statistically significant (<i>p</i> = 0.85). It was found that patients with longer duration of tinnitus had lower serum magnesium levels (<i>p</i> = 0.005).</p> Conclusion <p>Our study concluded that serum magnesium levels were not related to the incidence and severity of tinnitus. But serum magnesium levels in patients with long standing tinnitus were low in our study suggesting a role of magnesium supplements in the therapy of long standing tinnitus patients. Further studies are required to find out the role of nutrition in the management of tinnitus.</p>