João Hamilton Romaldini, born in São Caetano do Sul, São Paulo, Brazil obtained his M.D. degree in 1968 from "Escola Paulista de Medicina, Universidade Federal de São Paulo". He was Resident in Endocrinology at "Hospital do Servidor Público Estadual de São Paulo" from 1969 to 1971. He moved to Pisa, Italy where he became a Research Fellow at "Istituto di Endocrinologia, Universita degli Studi di Pisa", under his advisor Prof. Aldo Pinchera, from 1971 to 1973, where he developed his studies on thyroid immunology. His main aim was to improve an assay in vitro, for the Long-Acting Thyroid Stimulator (LATS) looking for the thyroid antigens for the LATS and the effects of LATS into follicles of isolated thyroid cells and the binding of radioiodinated thyrotropin to reassociated cells. He got his PhD from "Escola Paulista de Medicina" in 1974 and then he set up a thyroid research laboratory inside the Hospital Servidor Público Estadual where he became a pioneer by developing the TSH radioimmunoassay and developed an assay to determine the LATS-activity in the human thyroid tissue. Another meaningful study was related to the etiopathogeny of autonomous thyroid nodules. He also collaborated closely with the Department of Pharmacology, "Instituto de Ciências Biomédicas, University of São Paulo" and produced several studies related to ontogenesis of androgen receptors in hypothyroid and hyperthyroid rats as well as studies about thyroid-testis-pituitary axis. Dr. Romaldini dedicated a long-term effort to the study the immunopathology of Graves´ Disease and the influence of antithyroid drugs in the treatment of hyperthyroid patients. He is one of the world leaders concerning this subject and has published regularly in this area. Recently, his works have described the correlation between the subclinical thyroid diseases with dislipidemia and cardiovascular diseases. He is the author of about 70 original papers and book chapters. Dr. Romaldini was the LATS-General Secretary from 1983 to 1991, Vice-President from 1991 to 1993, President from1993 to 1995. He was also the President of "Sociedade Brasileira de Endocrinologia e Metabologia " from 1999 to 2000 He has been a Professor of Endocrinology at "Faculdade de Ciências Médicas" at Pontifícia Universidade Católica de Campinas, Campinas, São Paulo and Chairman of Postgraduate Course at "Hospital Servidor Público Estadual, IAMSPE". He had also been the director of Endocrinology Service in that Hospital for 17 years. Several of his former resident students are involved in the research work of thyroid.