Two hundred and forty-three urine specimens from 76 elderly institutionalized residents were obtained for urine culture, quantitative leukocyte count and urinalysis. Significant bacteriuria was present in 153 specimens (63%), including 33 (22%) with more than one organism. Pyuria (greater than or equal to 10 leukocytes/mm3) was present in 214 specimens (88%), including 116 (97%) with single organism bacteriuria, 27 (82%) with multiple organism bacteriuria, and 71 (80%) without significant bacteriuria. The leukocyte esterase test had a positive predictive value of 99% for pyuria but a negative predictive value of only 30%. The quantitative level of pyuria was associated with the level of proteinuria and inversely with pH. A relatively constant level of pyuria tended to persist over months to years in a given individual if bacteriuria persisted. Pyuria is significantly associated with bacteriuria in the institutionalized elderly, but is also common in the nonbacteriuric. The clinical significance of pyuria requires further assessment.