In previous studies made in the Endocrinology Clinic Tg.Mureş an increase of the thyroid cancer incidence was observed after 1986, the year of the Chernobyl accident. This elevation presented two peaks: between 1992–1994 and 2001–2003. The aim of our study was to analyse more accurately the variation of the thyroid cancer´s incidence among the in-patients hospitalized between 1991–1994 and 2001–2004, regarding mainly the nodular goiters. In the first period from 1516 goiter bearing cases 21 (1.38%), and in the second period from 2124 cases 90 (4.23%) were thyroid cancer. Between 1991–1994 from the nodular goiters 2.5% proved to be cancer, in 2001–2004 this percent increased significantly to 6.07% (p < 0, 001). The incidence of papillary and folliculary cancers rose predominantly. Concerning the thyroid cancer incidence in childhood, we would like to emphasize that there were no cases found before 1990. In the first period only one case was found and 3 children with carcinoma were registered between 2001 and 2004. The evident increase of the thyroid cancer may be attributed to the radiation exposure due to Chernobyl accident and to the progress of diagnostical methods.