Abstract: The present invention provides a device and method for desalinating saltwater which utilizes a heatable vessel wherein is placed a sufficient quantity of a salt which will absorb water of crystallisation and which has a dissolution index of not higher than 10?24. Saltwater is then added to the vessel and brought into contact with the salt, so that the salt will bind water from the saltwater and form a crystal hydrate. The excess saltwater with salt concentrate is drained from the vessel. The salt which has absorbed water tom the saltwater and formed a crystal hydrate is then heated in the vessel, and the pure water from the crystal hydrate is released as water vapour, which is collected and cooled to obtain desalinated water.