A retrospective chart review was performed on 54 patients with positive urine cultures during a 1-year period to assess the clinical significance of Aerococcus urinae. Based on predetermined criteria, patients were classified into 2 groups: those with urinary tract infections (UTIs) and those who were considered colonized. The majority of the patients were > or =65 years old and were female. Only 31% of patients with UTI and 45% of colonized patients had A. urinae isolated in pure cultures. Both groups had significant but similar underlying medical conditions, with urologic conditions being predominant. Significantly more patients in the UTI group had urinary catheters (P < .01). No direct complications or invasive disease was recognized in either group regardless of whether patients were treated with antibiotics. Apparently, A. urinae is a relatively avirulent organism when cultured from urine.