Objectives. To evaluate the bacteriological quality of fresh artisan cheeses and the supposed bactericidal action of Lactobacillus spp. Methods. A total of 39 samples of 100 g each of fresh artisan cheeses made from cow's milk were purchased in the seven municipal markets of the Pueblo Libre district of the city of Lima, Peru, between September and December 2001. The pH and the organoleptic characteristics (aroma and color) of each sample were recorded, along with the environmental temperature and humidity on the day of sampling. Using conventional microbiological growth techniques, an evaluation was made of the microbial load of mesophilic aerobic bacteria, total and fecal coliforms, Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, and Lactobacillus spp. In addition, the correlation between the presence of Lactobacillus spp. and the presence of the other microorganisms studied was analyzed. Results. The following average values for the microbial load were found: mesophilic aerobic bacteria, 7.1 × 106 colony-forming units per gram (CFU/g); total coliforms, 9.3 × 102 most probable number per gram (MPN/g); fecal coliforms, 8.3 × 102 MPN/g; Es. coli, 2.6 × 102 MPN/g; S. aureus, 3.1 × 105 CFU/g; En. faecalis, 4.6 × 102 MPN/g; and Lactobacillus spp., 1.6 × 105 CFU/g. For 97.4% of the samples the microbial load was above the maximum values permitted by the Government of Peru's Technical Standard 202.087 for the various microorganisms or groups of microorganisms: total coliforms (74.2% of the samples), fecal coliforms (58.6%), Es. coli (28.1%), and S. aureus (87.2%). The presence of Lactobacillus spp. did not preclude the presence of S. aureus and En. faecalis. Conclusions. The high microbial load in the cheese samples analyzed reflects deficiencies in the hygienic handling of the fresh artisan cheeses sold in the studied markets and also represents a health hazard for consumers. We did not find that the presence of Lactobacillus spp. impeded the growth of the other microorganisms studied in the cheeses.