Microscopic examination of urine is a rapid and accurate test for detecting the presence of significant bacteriuria, provided that proper care is taken with the collection and transport of the specimen and that the criteria for defining a positive test include the even distribution of at least two organisms throughout several oil-immersion fields. The sensitivity, specificity, and positive and negative predictive values obtained by examining 32,076 specimens were 94%, 90%, 90% and 99%, respectively.