Pea leaf weevil, Sitona lineatus L. (Coleoptera: Curculionoidae), is an insect pest that causes considerable damage to a wide range of cultivated and wild Fabaceae species. Both life stages of S. lineatus are considered to be harmful, adults feeding on leaves produce severe defoliation and larvae feeding on root nodules reduce nitrogen fixation for the plant. Highest fertility of S. lineatus was noticed on Pisum sativum L. and Vicia faba L. Due to species high reproductive potential, migratory behavior and cryptic larval habit, management of pea leaf weevil is a challenge. Existing pest management strategies in the Republic of Moldova relay mostly on the use of chemical pesticides. Also, issues associated with pest resistance to pesticides, effects on non-target species and impact to human health lead to a critical need in developing new solutions for pest control. In this regard, biological control agents are an efficient alternative to chemical pesticides, as a tool against insect pests that can support and ensure the food safety. The first step and the most significant criteria for effective use of microbial control agents in biological control is characterization of isolated entomopathogenic strains in terms of their virulence toward a target pest and identification of highly virulent strains. The aim of the present research was to evaluate the virulence of the newly isolated local strain of Beauveria bassiana Sl1/6 against adults of pea leaf weevil. In bioassay test, alfalfa was used as diet. Five serial dilutions of fungal strain in sterile distilled water were prepared to perform the test. By 1 ml of each dilution was spread on sterile filter paper in Petri dishes and 10 adults of S. lineatus were placed in each per Petri dish. Sterile distilled water was used as control. After inoculation insects were transferred in net cages with fresh alfalfa and kept at 25±1 ºC and photoperiod of 14 h. Insect mortality was recorded daily, all dead insects were removed from cages. The most effective of the tested concentrations for S. lineatus proved to be 0.969 × 106 spores/ml causing 100% mortality on the day five after treatment. The virulence of the strain expressed in LC50 values calculated according to Spearman-Karber formula represented 1.127 × 104 spores/ml. These results show that Beauveria bassiana strain Sl1/6 is virulent to pea leaf weevil and has potential as a biological control agent in leguminous crops pest management programs. The B. bassiana Sl1/6 strain was placed in National Collection of Nonpathogenic Microorganisms, and patented (Patent no. 4560 published in The Official Bulletin of Intellectual Property (BOPI) No. 4 from April 2018). This is the first report about bioassay against pea leaf weevil in the Republic of Moldova, using a local isolated B. bassiana strain. The results of the study are encouraging to continue investigation by evaluating the virulence of B. bassiana Sl1/6 strain against S. lineatus under field conditions and characterization of physiological and biochemical properties of the strain, for further development of a biopesticide formulation suitable for mass production.