Background: Although the microbiology of intraabdominal infection has been well described, the role of resistant organisms remains unclear. To evaluate the hypothesis that intraabdominal infections from resistant gram-positive cocci (rGPC) have worse outcomes compared to those with susceptible organisms, patient characteristics and outcomes were compared between these groups. Methods: Analysis of peritoneal infections was performed on prospectively collected data of all consecutive surgical infections from December 1996 to June 1999 at a university hospital. Intraabdominal infection was defined either by a positive peritoneal cavity culture or on clinical grounds (e.g., abscess), which prompted antimicrobial or surgical therapy. Resistant Staphylococcus and Enterococcus spp. were defined as those strains resistant to oxacillin, gentamicin, or vancomycin. Results: Compared to episodes of intraabdominal infection from susceptible organisms (n = 365), infections due to rGPC (n = 52) were associated with an increased severity of illness (p < 0.0001), longer time from admission to treatment (p < 0.0001), longer duration of therapy (p = 0.008), greater proportion of nosocomial infection (p < 0.0001), increased length of stay (p < 0.0001), and an increased mortality rate (9% versus 23%; p = 0.003). However, comparison of intraabdominal infection with rGPC to a group controlled for severity of illness demonstrated a prolonged time from admission until treatment and longer duration of hospitalization but a similar mortality rate between groups (17% versus 23%; p = 0.46). Conclusion: Intraabdominal infection with rGPC is an indicator of poor prognosis and severe illness. Although not an independent predictor of mortality, the significantly increased duration of therapy and prolonged duration of hospitalization may have considerable economic impact.