Staphylococcus aureus and Staphylococcus epidermidis have microbial surface components recognizing adhesive matrix molecules (MSCRAMM) adhesion proteins that enhance their biofi lm formation ability, as well as virulence factors that infl uence morbidity and mortality in hospital settings. In this work, four peptides analogous of the peptide LL-37 that were evaluated to inhibit biofi lm formation and its action potential on the expression of MSCRAMM proteins in clinical isolates through different tests, such as crystal violet, PCR and qPCR. In total, 96.8% of S. aureus were strong in biofi lm formation in contrast to 48.4% of S. epidermidis. sdrG and sdrF genes were present in 100% of S. epidermidis strains and in all isolates. In S. aureus, specifi c genes that code for MSCRAMM proteins were detected: clfA (89%), clFB, sdrC and fnBA (94%). The peptides did not show hemolytic or cytotoxic activity. In this study, it was evidenced that of the peptides DLL37-1 at a 5 µM concentration was an effi cacious antimicrobial agent and depicted greater biofi lm inhibition in both bacterial species. Exhibiting a signifi cant inhibition rate in S. aureus, this peptide caused a negative regulation in the expression of the genes clfA and sdrC, showed greater biological activity.