The blood cell characteristics, blood cell dimension and hematological values of sand lizards were studied in eighty sand lizards during March-July, 2006. These lizards were obtained from provinces in the Northeastern part of Thailand. The results gave following information: The blood cell characteristics of sand lizards presented distinct morphology. The blood cell characteristics of sand lizards were similar to those of other reptiles. Red blood cell width and length, diameter of lymphocyte, monocytes and heterophils of the male sand lizard were significantly larger than those of the female. On the other hand the diameter of male basophil was significantly less than that of the female. Packed cell volume, hemoglobin concentration, total red blood cell count and heterophil of the male sand lizards were significantly higher than those of the female. In contrast, the basophil and eosinophil of the male sand lizards were significantly lower than those of the female. These findings indicated that sex influenced the hematological values of sand lizards.