Since the number of microorganisms that are resistant to antibiotics has been increasing steadily, the need for combating these pathogens requires new pharmaceutical agents. To produce these substances, new models have been developed in recent decades. In our study, the venom of Agelena labyrinthica (Clerck, 1757) (Araneae: Agelenidae) was tested against ten bacterial strains, specifically, testing 1/100, 1/10 and 1/1 fractions of diluted venom against these bacteria. While the 1/100 dilution was successful in only one of ten bacterial strains, the 1/10 and the 1/1 were effective on six of ten bacterial strains. The most effective results, among these three different concentrations, were observed on Bacillus subtilis. The other five strains that were also sensitive to the dilutions showed similar inhibition zones. Morphological alterations on bacterial cells and comparison with normal cells were accomplished by scanning electron microscopy (SEM). The venom-treated cells, due to their loss of cytoplasm, shrank and presented cell wall depression.(AU)