In the context of the radiation exposure of the Ukrainian population resulting from the Chernobyl accident, the quantification of the thyroid doses due to iodine incorporation is of special interest. This first part of a series of planned publications deals with the dose and risk estimation for Kiev citizens. Although these doses are expected to be considerably lower than those for some other regions of Ukraine, the investigations started with this population because of the availability of rather reliable measurements and because of the size of this population, The methods developed allowed the estimation of individual thyroid doses. The average values of individual thyroid doses for five age groups (birth years 1983–1986, 1979–1982, 1975–1978, 1971–1974, and < 1971) are 104, 62, 19, 18, and 41 mGy, respectively. The collective thyroid doses were estimated as 83 × 103 person-Gy for those born before 1971 and as 38 × 103 person-Gy for younger inhabitants. The numbers of expected thyroid cancers in the whole Kiev population are 66 and 130, respectively.