The gray wolf (Canis lupus) is a mammal from the family Canidae, order Carnivora. In the past, the distribution of the gray wolf included almost all of Eurasia and North America, but due to negative human influence, it has been eradicated from many areas. The gray wolf is a legally protected species, and its population is monitored through various methods for the purpose of species management, with determining a complete blood count being one of the best indicators of animal health. However, there is an insufficient number of published data on the hematology of free-ranging wildlife, including the gray wolf. Sometimes, due to the inability to store blood, the unavailability of hematological instruments during fieldwork, or insufficient blood quantity for a complete hematological analysis, evaluating a blood smear may be the only method to obtain information about hematological changes. In this study, blood smears from 16 free-ranging gray wolves were examined to determine the total leukocyte count, differential blood count, possible changes in the morphology of red blood cells, leukocytes, or platelets, and the presence of cellular inclusions, hemoparasites, or other microorganisms. Statistical analysis was used to identify significant differences in certain hematological parameters depending on gender. The estimated total and differential leukocyte counts were comparable to previous literature data obtained using hematological instruments. Therefore, this study demonstrated that the blood smear evaluation method is of great assistance in determining the hematological and overall health status of the animal. It is a very simple, fast, and cost-effective method, especially useful in field conditions. In this study, a statistically significant difference in absolute eosinophil count was found between the male and female groups; however, due to the limited literature data about this difference and possible causes of it, further research is needed.