Bacteriological investigation of urine often shows the presence of alpha-haemolytic streptococci, but the clinical significance of this finding may be unclear. Among the alpha-haemolytic streptococci found in urine is Aerococcus urinae, which is pathogenic.We present a prospective study of the prevalence and antibiotic susceptibility of A urinae in urine samples sent to a microbiology laboratory in Norway.Seven out of 27 alpha-haemolytic streptococcal isolates were A urinae. This represents 0.3% of all urine isolates from our laboratory. Appropriate methods for identification and resistance determination are described.Microbiological laboratories should include identification of A urinae in their diagnostic repertoire. Recommended treatment against A urinae is ampicillin or nitrofurantoin.