Nowadays life styles have been changed due to technology improvement. Part of this change includes people's nutrition style which has headed for using removed bran cereal, treated meat derivatives and high percentage fat and sugar foods. Moreover, vegetables and nutritional fibers share in daily diet is reduced. This developing trend has caused an increase in obesity and prevalence of some chronic diseases such as diabetes, heart diseases and some sorts of cancers. Above all, snacks are playing a leading role as main course share in daily diet is decreased due to developing urban life style. Altering nutritional values of snacks can alter society's nutrition. One of the compounds that can be used to enrich snacks especially bakery products is fiber. Tremendous number of researches shows useful effects of using fiber in protecting people from heart diseases and cancer, regulating blood fat, glucose absorption and preventing constipation. Thus, in order to improve nutritional properties of snacks, probability of producing fortified fruit bar as a functional food and low calorie product was investigated. Apple snack consists of two parts, crust and core. Apple snack crust is a bread cover that dough is formulated based on bread dough and core of this snack is apple, cinnamon and sorbitol. in order to improve nutritional properties of this product diet fibers are added. Apple and potato fibers are substituted in three levels of 4, 6, and 8 percents. Physical and chemical properties of dough and product were studied. Effect of adding fiber on rheological properties of dough and product were also investigated. The results of rheological properties of dough investigation showed substituting wheat flour by apple and potato fibers caused an increase in water absorption and dough stability time. Potato fiber in 4 and 8 percents substitution does not induce a meaningful difference in stability time with low fiber dough. Though, it was meaningful in the 6% level which means dough structural solidarity of potato fiber is more than other percentages. Comparison between apple and potatofiber shows water absorption value in enriched dough is increased with potato fiber. By adding potato fiber in all levels, stability of dough is better than low fiber dough. By using apple fiber, dough apparent viscosity decrease rate was increased. By substituting apple and potato fibers by flour, dough arival time and tensile strength were increased in all three levels. Dough extensograph results show a decrease in tensile and an increase in resiliency of dough containing apple and potato fibers as compared to reference sample. Dough volume extension results while fermentation show wheat flour substitution by apple and potato fibers causes a decrease in dough volume. Test results on apple snack show wheat flour substitution by apple and potato fibers causes a decrease in apple snack special volume and increase in yellowness and firmness of texture. Organoleptic test results show the more the fiber amount, the less customer acceptance is the apple snack by using apple and potato fibers.It was shown that the end user satisfaction based on surface color properties,apple snack core and chewability is reduced. Overall acceptation of snack with potato fiber is more than others, however it is less acceptable as compared with snack without fiber. Keywords: Rheological properties, Diet fiber, Apple fiber, Potato fiber, Apple snack