Changes in the volume of parsley root slices during drying and rehydration were investigated. Samples were cut into slices 3, 6, and 9 mm thick. Temperature of drying air equalled 50, 60, and 70C. Drying was conducted in laboratory dryer and constant mass was achieved. Rehydration was tested within the range of 0-6 hours in water at 20oC. The volume changes of parsley root slices during drying and rehydration were measured by buoyancy method using petroleum benzine. The investigations showed that slice thickness and drying temperature influence the course of changes in the volume of dried parsley root slices during rehydration. Drying temperature influences the course of changes in the volume of parsley root slices during drying, too, but the influence of slice thickness was slight. None of the rehydrated samples reached the state of the product before drying. For the same moisture content the volume of a dried sample was always higher than the volume of a rehydrated sample.