Even though Stomatococcus mucilaginosus is considered indigenous oral-pharyngeal flora, cited literature and case reports indicate that it can be the cause of infectious conditions. Tested strains were isolated from blood, the oral region, and wound sources. The organism was routinely misidentified or not identified by conventional or commercial systems (Vitek, STAPH-Trac). Four antimicrobial diagnostic disks for example, bacitracin (0.04 units; Taxo A), furazolidone (100 micrograms), novobiocin (5 micrograms), and polymyxin B (300 units), were evaluated as possible addition to previously applied biochemical characteristics that differentiate between S. mucilaginosus, Micrococcus sp., and coagulase-negative staphylococci. Consistent antimicrobial susceptibility patterns among our isolates to the diagnostic disks produced applicable characteristics for discriminating S. mucilaginosus from similar microorganisms. However, therapeutic choices of antimicrobial agents should be guided by individual organism susceptibility test results because of variable, often resistant patterns to beta-lactams, aminoglycosides, macrolides, new fluoroquinolones, and sulfonamides.