Gnaphosa lugubris is a ground spider species found from Europe to Central Asia. The difficulties in interpretation of diploid chromosome numbers, sex chromosome systems and the need for modification of the applied method for different species has restricted the number of studies in spider genetics. Despite these difficulties in chromosomal studies, Giemsa staining is the most effective method for studying gnaphosids. This method is carried out in three steps: hypotonic application, fixation and squashing the tissues and air drying. In this study, the chromosomal characteristics of Gnaphosa lugubris were investigated in male specimens which were collected from the central part of Turkey. As a result, the diploid chromosome number and sex chromosome system were determined as ♂X₁X₂/♀X₁X₁X₂X₂ type. All chromosomes were telocentric and the gradual decrease in the lengths of autosome pairs was from 10±0.46% to 4±0.32%. X₁ was medium-sized and X₂ was the smallest element in the karyotype. The results which have been presented for the first time will contribute to increasing our knowledges about cytogenetic properties of the ground spiders.