Osmotic dehydration (OD) is a water removal process that can be employed to obtain minimally processed food with a longer shelf life and improved nutritional value. Osmotic dehydration is a useful technique for the preservation of fruits because it results in a reduction in water activity (aw) while promoting a higher quality product than traditional drying allows. Osmotic dehydration is a method applied for water removal of fresh foods, by immersing pieces of the food in a solution of higher osmotic pressure, and hence of lower water activity than the food. This solution is sometimes referred to as a hypertonic solution in the literature. Water passes from the food into the solution under the influence of the osmotic pressure gradient. In this process, the walls of the cells in the food act as semi permeable membranes. However, the membranes are not completely selective. Some soluble natural substances, such as organic acids, sugars, salts, and vitamins, may be lost with the water, while solutes from the solution may penetrate into the food. This gain of solutes by the food can contribute to the reduction of its water activity, but may affect the taste of the product. As a pretreatment to drying, OD can reduce the moisture content of a plant by approximately 50%, can also reduce aroma losses and enzymatic browning and increase sensory acceptance and the retention of nutrients. The osmotic treatment also allows for an increase in the nutritional value of fruits and vegetables due to the impregnation of minerals and vitamins into its porous structure. OD is an important tool to reduce the water content with little bit damage on the quality of fresh products. This can be done with the mild heat treatment of product at luke warm temperature (30-50°C), so that temperature did not affect the properties of cell membranes, which was necessary to maintain the osmotic phenomenon. Generally the plant tissue is continuously immersed in the osmotic medium because the oxygen will not be exposed so that there is no need of use of any antioxidants to protect against enzymatic and oxidative discoloration. The sweet potato slices were osmotically dehydrated. The osmotic process was carried out at different NaCl concentrations (0, 5 and 10% w/w) and fixed sucrose concentration (50% w/w), solution temperature (40°C) and agitation (90 rpm).The initial concentration of solutes in the solu¬tion can affect the rate of water loss. Sugar concentrations in the range of 40 to 70% are used. Sometimes, a higher concentration may be achieved by solid gain, which can affect the taste of the product by making it too sweet.