Fish were studied in different salinity and temperature groups to determine the effects of these stresses on hematological parameters in common carp (Cyprinus carpio). The treatments include three temperature groups: 20, 25 and 30°C, each one with three salinity levels: 10ppt, 5ppt and fresh water. After 3 weeks, blood samples were collected and Hemoglobin (Hb), Hematocrit (Hct) and Red Blood Cells (RBC) were measured and MCV, MCH and MCHC were calculated (fish mean weight: 47.37g). With temperature and salinity increases, the number of RBC was significantly increased (P<0.05). But Hct and Hb decreased with temperature increase (P<0.05). In higher salinity and temperature, MCH and MCV were lower than lowest ones (P<0.05). MCHC was higher in moderate salinity (5ppt) and temperature (25°C). Blood parameter changes generally occure due to change in RBC properties such as number and size and Hb content or change in plasma volume.