Increasing temperatures negatively influence pollination and fruit set of the plants. Such temperatures also have significant negative effects on leaf, stem and root development. Especially in greenhouse production activities and practices in southern regions of Turkey, plants are often exposed to high temperatures. Beans are commonly produced and consumed in almost every part of the world and they are negatively influenced by high temperatures. This study was conducted to see the efficiency of potassium treatments in reducing the negative effects of high temperatures on yield and quality of beans. Zulbiye bean cultivar sensitive to high temperature stress and V71 bean genotype which was also previously identified as sensitive to high temperatures were used as the plant materials of the experiments. Bean seeds were sown in 2 It pots filled with 1:2 perlite:peat mixture. Different potassium (K) doses of 0 (control) ppm K, 500 ppm K, 100 ppm K and 2000 ppm K were applied to seeded pots. Seeding was performed as to have two plants in each pot and experiments were conducted in ran-domized blocks factorial experimental design with 4 replications with 4 pots in each replication. Pots were irrigated with Hoagland nutrient solution throughout the experiments. At the seedling period, control plants were grown in a greenhouse with temperatures of 20 - 25 degrees C, but the treatment groups were placed in a separate tunnel in the greenhouse for high temperature treatments. Tunnel temperature and relative humidity were measured with Hobo data logger and temperatures were observed as between 33 - 37 degrees C. Plant height, fresh weight, root collar diameter, number of leaves, leaf size, leaf relative water content and membrane damage index values were analysed 12 days after seedling period. Well growth and development were observed in high temperature-sensitive bean genotypes with increasing potassium doses, especially with 2000 ppm K dose and potassium treatments reduced the negative effects of high temperatures on investigated growth and development parameters.