Data of long-term researches (2015–2018) in southern forest-steppe zone of the Republic of Bashkortostan, is justified theoretically and experimentally the mode of irrigation of potatoes on leached chernozems of unsatisfactory, satisfactory and good ameliorative condition of irrigated lands. For the growing periods of potatoes with different heat and moisture supply, the number of watering, the timing of their implementation, irrigation and irrigation norms are established. On lands with unsatisfactory meliorative state the number of irrigation depending on weather conditions of potato vegetation period varied from 0 to 3 (1.5 on average) with average irrigation norm – 990 m3/ha. With satisfactory meliorative state of lands the number of irrigation on average increased from 0 to 4 (2.3 on average) with irrigation norm – 1305 m3/ha. On lands with good meliorative state the number of irrigation was the highest – from 1 to 5 (3 on average) with average irrigation irrigation norm is 1653 m3/ha. It was noted that in the dry periods of potato vegetation the greatest number of watering was carried out (3–5 watering), and in the wet periods (2017) watering was not carried out except for the area with a good reclamation state, where only one irrigation was carried out by the norm of 550 m3/ha. Water consumption of potato was studied in dynamics as a whole during the growing season and the months of the growing season depending on weather conditions of vegetation period and land reclamation condition of irrigated lands, as well as in the control (without irrigation). The lowest total water consumption was in the area without irrigation and averaged 226.8 mm. In irrigated areas, its values increased to 319-353.4 mm. The average daily water consumption varied from 2.12 to 3.3 mm. The highest rates of potato water consumption were observed in June and July, and the lowest – in May and August. In the total water consumption of potatoes on the site without irrigation, the largest share was occupied by atmospheric precipitation and in addition to them the arrival of moisture from the soil. Irrigation water was used in irrigated areas along with precipitation, the share of which was 30.2–46.1 %.