This work has been done to investigate physiological values of some hematological parameters of peking ducks. For this purpose 20 healthy peking ducks have been studied. Total red (R.B.C.) and white (W.B.C.) blood cell counts by routine methods in Thoma hemocytometers after diluting with Natt-Herrick solution, packed cell volume (P.C.V. = Htc) by the microhematocrit centrifuge method, hemoglobin (Hb) by the cyanmethaemoglobin method were carried out. Blood films were stained by Pappenheim's method and the percentage of neutrophils, lymphocytes, eosinophils, basophils, and monocytes was estimated on a differential count of 200 cells. The mean values have been found as follows: R.B.C. = 3,835 x 10(6)/mm3, W.B.C. = 15.950/mm3, Hb = 12 g%, P.C.V. = 36,15%, neutrophils = 62,10%, lymphocytes = 30,95%, basophils = 5,8%, eosinophils = 0,6% [corrected], monocytes = 0,6%.