The thyroid gland is the main regulator of metabolism and affects all bodily functions. The most common oral manifestations of hypothyroidism are macroglossia, dysgeusia, late teeth sprouting, poor periodontal health, altered teeth morphology and delayed wound healing. For the purpose of proving the association between hypothyroidism and hyposalivation, Pubmed was searched in the last 15 years with the keywords: hypothyroidism, hyposalivation and xerostomia. Six research studies were found that explored the interconnection of hyposalivation, hypothyroidism, xerostomia, Sjögren's syndrome and Hashimoto's thyroiditis. Varoius authors concluded that hyposalivation exists in people with hypothyroidism/Hashimoto's thyroiditis who do not take hormone replacement therapy and that hyposalivation disappears when patients receive thyroid replacement therapy. Significantly reduced unstimulated salivary flow than in the control group was found in people having hypothyroidism/Hashimoto's thyroiditis along with the Sjögren's syndrome/xerostomia, while stimulated salivary flow is not significantly reduced. We might conclude that patients with untreated hypothyroidism have hyposalivation and when they begin with the replacement therapy with thyroid hormones, the salivary flow rate becomes normal.