Objective: To investigate the decrease in hemoglobin concentration and hematocrit during elective surgery.Methods: This was a prospective study being performed in Nemazee Hospital of Shiraz University of Medical Sciences. We included a total of 50 American Society of Anesthesiology (ASA) I and II patients undergoing elective minor surgeries. Perioperative fluid administration was performed for all the patients and hemoglobin and hematocrit levels were measured three times: Once before the operation, once one hour after start of operation and once in the recovery room. Values were compared using paired sample t-test.Results: The mean age of the patients and controls was 39.66 ± 8.27 years. Hemoglobin level decreases significantly after one hour (p<0.001) and after the end of operation (p<0.001). In the same way hematocrit level was decreased significantly after one hour (p<0.001) and after the end of operation (p<0.001).Conclusion: In this patient population undergoing elective minor operations, there was significant decrease in the hemoglobin and hematocrit levels in response to the IV fluids administration.