To evaluate the features of pyuria related to the bacteriuria, 140subjects were studied from Jan. 1987 to Dec. 1987. They pyuria was frequently developed from the age 30 to 60 years old, and male to female ratio was 1:1.41. The most common disease was urethrocystitis that was shown 42.8%. Common precipitating factors were urethral catheterization (25%) and urinary tract obstruction (11.4%). Through the observation, symptomatic pyuric patients were 66 subjects (47.1%), and the subjects with significant urine culture were 121 subjects (86.4%). In the urine culture, the most common bacteria was E. coli (41.4%), and the next was Pseudomonas (19.3%). A large percentage of E. coli and Pseudomonas was susceptible of amikin. The pyuria due to S. epidermidis and Accinatobacter was well treated. High therapeutic rate was observed in the acute pyelonephritis (71%) and urethrocystitis (67%). In the persistent urinary tract infection, there were relapsing (22 cases) and recurrent urinary tract infection (16 cases).