Osmotic dehydration of pumpkin v. Melonowa Żółta by 5 x 50 x 50 mm in shape of plate was carried out in the diffuser enabling the flow of osmotic solution and constant temperature. Solutions of saccharose and starch syrup at temperature 30, 50 and 80°C were applied to this process. Time of osmotic dehydration of pumpkin was changed since 0 to 180 min. Simultaneously before osmotic dehydration of pumpkin at 30 and 50°C was preliminary thermal treatment for 3 minutes immersion in water at temperature 80°C. The water content and water loss from osmo dehydrated pumpkin in saccharose solution was depended from temperature and kind of osmotic substance as well as in small stages from preliminary thermal processing. There was no temperature and thermal treatment effect on pumpkin during osmotic dehydration in starch syrup solution at 30-50°C temperature range; the differences were appeared in comparison 80°C only. The highest value of water loss to solids gain relation was noted down in osmo-dehydrated pumpkin in starch syrup solution at temperature 30°C without of preliminary thermal treatment.