Objectives: This study is focused on internal exposure to ²¹⁰Po, a highly radiotoxic α-emitting radioactive element. This isotope is important in evaluating internal exposure among industrial workers, especially in sectors that handle naturally occurring radioactive materials (NORMs), where polonium can be present in workplace as a result of its release in thermal processes and other processes in which enhanced NORMs are utilized. The aim of this paper is to present a validation of an implemented method for determining ²¹⁰Po in urine and its application in industrial sector where internal ²¹⁰Po contamination is a potential risk. Material and Methods: The presented method for determination of ²¹⁰Po activity in urine involved radiochemical preparation of 24-hour urine samples followed by spontaneous deposition of polonium on a silver disc and measurement by α spectrometry. The method was applied to urine samples analyzed as part of the validation process as well as to urine samples collected by industrial workers. Results: The method was validated in interlaboratory comparison and implemented in Radiation Protection Measurements Laboratory (Laboratorium Pomiarów Dozymetrycznych – LPD) of the National Centre for Nuclear Research in Poland. Precision, selectivity and detection limit were also characterized in validation process. The implemented method allowed to obtain relatively high values of tracer recovery (²⁰⁹Po), on average at a level >70%. Conclusions: Conducted analyses of urine samples collected from selected industrial workers confirmed that radiation exposure to ²¹⁰Po at positions directly related to the technological process was higher than at other positions, however committed effective doses were on the safe level. Int J Occup Med Environ Health. 2026;39(2)