The high temperature due to climate change may result in the intensification of several drought and heat stress on crops including potato. These abiotic stress affect on potato development staages; sprout development, tuber initiation and maturation. Potatoes need moderate amounts of nitrogen and cool night for good tuber growth. Especially, high temperature in soil will delay tuber initiation and induce malformation. Therefore, to identify quickly heat tolerant lines and breeding potato lines adapt to high temperature in the field are needed. The objectives of this study were as follows; To apply in vitro screening method for identifying potato lines adapted to high temperature conditions. To verify these results under field assays carried out under natural high temperature field conditions. We used in vitro screening methods with breeding lines from Intranational Potato Center(CIP) under three temperature regime, 18℃, 25℃ and 30℃. All breeding liens had some genotype that produced microtubers at 18℃ and 25℃, with a clear tendency for lower percentage of tuberization at the high temperature. To verify in vitro screening methods for heat tolerance lines, we carried out natural high temperature filed evaluation at Tacna, La Molina and Sanramon in Peru. The results of both the in vitro test and the field assay showed clear relationship and similar expression of tuberization percentage. This finding supports the use of the in vitro assay as a rapid screening methods that represents performance at the field level. But the correlation between performance of the breeding lines under the in vitro and field condions was low. This could be due to differential response to breeding lines to characteristics of the field environment, such as soil salinity, drought, which were not represented in the in vitro assay.