Objective: To update concepts on thyroid hormones functioning in cattle. Materials and Methods: Through review of available literature from the last 25 years included in the BBCS-LILACS, Fuente Academica, IB-PsycINFO, IB-SCI, IB-SciELO, Scopus and Scirus data bases as well as in historical articles, texts and references cited in work published. Results: The information obtained concerning the objectives proposed in the present review allows classifying five sections as follows: synthesis, metabolism and transport; thyroid function in growth; thyroid hormones and nutrition; action of thyroid hormones on reproduction and milk production; and disorders of the thyroid gland in ruminants. Conclusion: nutritional status is a key factor in the production of thyroid hormones which play a crucial role in the development, growth, reproduction and production of cattle.