We performed systematically studies of tritium concentration in the environment in Ukraine since 1988. Attention was paid to different aspects of tritium: background levels, tritium in the vicinity of working NPP facilities installations and tritium in precipitation. Monitoring of background levels of tritium was performed for same regions of Ukraine and include sampling sites for surface, underground and tape water. Data, corresponding of NPP facilities, was obtained for all Ukrainian NPP’s, including of “Shelter” object at Chernobyl NPP. Tritium in precipitation was measured in samples collected for hydro meteorological network of Ukraine by corresponding personal for all territory of Ukraine (more than 35 observation stations). Modem ultra low-level liquid scintillation spectrometer Quantulus 1220TM produced by Wallac Oy was used for sample measurement. Sample preparation and measurement technique we applied depends on sample nature and aim of study. For most cases composition of 8 ml of water and 12 ml of Optiphase HighSafe 3 cocktail in 20-ml plastic vial to 1,1 Bq/L. All samples having high tritium concentration were measured with counting limit of 500 or 2500 counts. All data obtained for tritium include more than 10000 results, which include 2900 samples for precipitation and more than 4000 water samples for NPP’s monitoring network. Summarized results are: average tritium activity in precipitation 3,7±0,3 Bq/L, opened reservoirs of drinking water 4,2±0,9 Bq/L, and in vicinity of NPP – of hundreds to thausend Bq/L. Irradiation doses for population corresponds to 0,1 mSv per years.