Abstract It is well known that there are halophilic or non-halophilic bacteria in salt, soak liquors, salted and soaked hides/skins in high numbers in leather industry. These bacteria have several hydrolytic enzymes which cause irreversible defects on finished leather product. However, antimicrobial agents are utilized to control bacterial population in soaking process, these agents have not sufficient efficacy due to inadequate application of these agents or the presence of antimicrobial-resistant bacterial strains in soak liquors. In this respect, alternative agents or strategies may be helpful for controlling bacterial population. For this purpose, ten isolates were obtained from different soak liquor samples and the antibacterial effects of acetone extracts of Parmelia sulcata and Hypogymnia tubulosa lichen species were evaluated on these isolates. Colony morphologies on agar plates, Gram staining, oxidase and catalase tests, bacterial growth on several selective media of these isolates were investigated. They were Gram-positive, rod-shaped and catalase positive. While bacterial growth was observed on Manntiol Salt Agar, Baird Parker agar, 5% sheep blood agar in most isolates, no growth was detected on Eosine-methylene blue agar and Cetrimide agar. Additionally, a ntibacterial activities for acetone extracts of Parmelia sulcata and Hypogymnia tubulosa against these isolates were tested at certain concentrations of 240, 120, 60 and 30 µg/ml . Hypogymnia tubulosa extracts were found to be more successful in comparison to the extracts of Parmelia sulcata on tested isolates. T hese tested lichen species can be used to control the population of bacteria in the soaking process and also to prevent potential defects on the skin that may be seen in subsequent tanning processes due to the development of these bacteria.