Determining the water requirement of plants is a necessary condition for implementing systematic irrigation and improving water productivity in the agricultural sector, which is needed considering the country's water resources and their intensification due to mismanagement and climate change. The aim of the study was to determine the water requirement and plant coefficients of three mini-tuber potato varieties in greenhouse conditions in Minadasht County, Isfahan Province. For this purpose, three potato varieties, Sante, Agria, and Desire, were cultivated in three replicates in a microlysimeter with the aim of producing tubers along with grass, and by maintaining the daily health of the cultivation bed at the field capacity, the water requirement was determined during the growing season. Also, the plant coefficient of the three mini-tuber potato varieties was calculated at different growth stages including growth, development, middle, and end. The results showed that the water requirement of mini-tuber potato varieties for the three studied varieties was in the range of 2.69 to 0.77 mm during the growth period. The average plant coefficient for the three studied cultivars in the four growth periods of initial, development, intermediate and final were 0.49, 0.8, 1.14 and 0.87, respectively. Considering that Isfahan province has many parts of the country with severe water resources and in greenhouses water and nutrients are consumed simultaneously, therefore, it is necessary to increase the productivity of water and other resources at different stages of plant growth with quality and quantity of the product.