This study was conducted during 2015 and 2016 seasonsFaculty of Agriculture andNatural Resources, Aswan University, to compare two species under salinity stress; Dill (Anethum graveolens) and Fennel (Foeniculum vulgare). Also, the study aimed to identify the biochemical changes to understand tolerance mechanisms. In pots experiments, plants were exposed to three levels of salinity stress 1000, 2000, 3000 ppm as well as control.Data showed that significant reductions were observed in shoot dry weight and seeds yield in Dill plants, but not in Fennel plants. Both species showed significant increases of Na⁺ accumulation in plants shoot under stress. The accumulated Na⁺ was much higher in Dill than that in Fennel at high salinity stress level (3000 ppm). Fennel had higher K⁺ content under control and 1000 ppm treatment. Intensity of proteins band relatively decreased with increasing salinity stress level. Moreover, some protein bands disappeared under salinity stress including130 and 10 KDa for Fennel plants, and 175, 95, 80, 48, and 24 KDa for Dill plants. These results indicated that Dill suffered more damages under salinity stress because of accumulated Na⁺ whether on growth and yield level or biochemical level, while Fennel had high tolerance ability to stress. Moreover, both species showed acclimation mechanism to salinity stress through biochemical changes that could be required to avoid dangerous affects and to alleviate salt stress. We recommend using saline irrigation water for cultivation of Fennel plant under SouthValley and Aswan conditions.