Shrinkage of high-moisture foods is primarily due to moisture loss. Factors affecting shrinkage are discussed both for respiring and nonrespiring products in refrigerated and frozen storage. Each factor is discussed in relation to its effect on the driving force and/or the resistance to moisture transfer. The driving force (water vapor pressure difference) is affected by several factors including the relative humidity of ambient air, evaporative cooling, respira­tory heat generation, and dissolved solids. The resistance is affected by air velocity, product shape, surface structure, and other variables. Other effects discussed are those pertaining to packaging, fluctuating storage temperature, and bulk storage.