Spiders, as all other arthropods, have an open circulatory system, and their body fluid, the hemolymph, freely moves between lymphatic vessels and the body cavities. The hemolymph can be considered as a multifunctional organ, central for locomotion, respiration and nutrition, and it amounts to approximately 20 % of a spider’s body weight. Any injury includes not only immediate hemolymph loss but also pathogen attacks and subsequent infections. In spiders, the immune system is localized in hemocytes which are derived from the myocardium cells of the heart wall where they are produced as prohemocytes and from where they are released as different cell types into the hemolymph. They contribute to the defense against pathogens by phagocytosis, nodulation and encapsulation of invaders. The goal of this research is to consider the number and morphological characteristics of hemocytes of the spider species Geolycosa vultuosa. In this research the staining method May-Grünwald giemsa (MGG) was established as the best to describe morphological characteristics of hemocytes (cell size and their nuclei, presence of vacuoles, organels and granules) which is a significant contribution to the field of spider physiology that still lacks research. Data provided in this research will enable easier recognition of hemocyte types in spiders in general and further easier research in the field of spider hematology and their immune response.