The present study was conducted to investigate the effect of high salinity on some stress parameters of common carp (Cyprinus carpio), which gradually exposed to salt concentrations of 5, 10 and 15 g/L, as well as tap water (control 0.1g/L) for 90 days. 80 fish were randomly distributed on eight glass tanks with 2 replicates as 10 fish /tank at average weight of 15 ± 3 g to study the effects of salinity on the number and percentages of the chloride cells in gills, beside the effect of salt concentrations on metabolism and the cost of the energy spent for osmoregulation through studying the oxygen consumption. Chloride cells in the gills were increased to 10.36, 14.80, 11.95 x 105 cell /g scraped matter. While the percentage of the chloride cells, increased to 11.34, 12.14 and 11.90% in the salt concentration of 5, 10 and 15 g/L, respectively, in comparison with the control treatment (8.42%). The rise in salinity was accompanied with an increase in the average of the oxygen consumed by common carp as it amounted 150,181.25 and 196.87 mg O2 /kg/h when the salinity increased to 5,10 and 15 g/l respectively, in comparison with the control treatment (85.93 mg O2 /kg/ hour), and this increase in the oxygen consumption resulted in an increase in the average of the energy consumed by fish that reached 0.50, 0.6 and 0.66 kcal (kg/h) with the increase of salinity to 5,10, and 15 g/L, respectively, in comparison to control (0.28 kcal/kg/h).