Abstract: Blood cell characteristics and hematological values were studied in thirty-three healthy free ranging-red jungle fowl (Gallus gallus) (male, n = 17; female, n = 16), at the age of 2-3 years, which had been free ranged at Nakhonratchasima Zoo, Nakhon Ratchasima province northeastern, Thailand. The results revealed the following information: the morphologic features of blood cells from red jungle fowls were similar to those of other species of chicken. TRBC, Hb, PCV, MCV, MCH, MCHC, TWBC, lymphocyte, heterophil, monocyte, eosinophil, basophil, thrombocyte of Red Jungle Fowl were 4.43±0.67 (3.76-5.10) x106 cells μL•-1, 13.63±2.28 (11.35-15.91) g %, 41.34±6.71 (34.63-48.05) %, 93.57±7.97 (85.60-101.54) fl, 30.80±2.24 (28.56-33.04) g dL•-1, 30.41±1.60 (28.81-32.01) pg, 9,140±3,839.27 (5,300.73-12, 979.27) cells /μL, 74.6±20.27 (54.33-94.87) %, 21.83±19.18 (2.65-41.01) %, 2.00±1.47 (0.53-3.47) %, 3.50±1.34 (2.16-4.84) %, 1.67±2.79 (0-4.46) %, respectively. Width and length of red blood cell of red jungle fowls were 6.70±0.57 and 10.65±0.59 μm. Diameter of heterophil, lymphocyte, monocyte, eosiniphil, basophil and thrombocyte of red jungle fowls were 10.85±0.75, 5.60±0.48, 9.35±1.04, 8.25±0.91, 7.63±1.40 and 4.25±0.72 μm, respectively. Moreover, total red blood cell, hemoglobin concentration and packed cell volume of males red jungle fowl were higher than females (p<0.05). Finally, MCV, MCH and MCHC of the male and female red jungle fowl were not significantly different (p>0.05).