Introduction. Tuberculosis is one of the leading causes of morbidity and mortality and almost one-third of the world is infected with this disease. Tuberculosis has been reported in many parts of the human body. But thyroid gland involvement is extremely rare and its true incidence is unknown. Case Presentation. We present the case of a 26-year-old woman who presented with a thyroid cyst which turned out to be a primary mycobacterium tuberculosis infection. Conclusion. The correct diagnosis of thyroid tuberculosis is important because of the availability of medical treatment and the limited role of surgery.