Background: Hematological and biochemical analyses of blood can be of great importance for studying the biology of species and determining the health status of animals in both the wild and captivity. In order to determine baseline ranges for the nose-horned viper Vipera ammodytes, we determined the blood cell morphology and measured 20 hematological and 5 biochemical variables from the blood samples taken from 31 (17 males and 14 females) healthy specimens of nose-horned viper caught in the wild at the beginning of autumn. Results: Most of the measured parameters and blood cell morphology were similar to those reported for other reptile species. The males showed a significantly higher eosinophil count and higher mean cell hemoglobin (MCH) and MCH concentration values, while the females had a significantly higher mature erythrocyte count. The erythrocyte differential counts showed balanced hematopoiesis in this part of the annual cycle. Conclusions: We suggest that these results can be used as a baseline for determining hematological values and blood cell morphology for V. ammodytes, as well as in further studies including monitoring and determination of the health status of this species, especially of animals kept in captivity for antiserum production. This is the most complete report regarding hematological parameters of this endangered snake species.