Aim The number of elderly patients with pneumonia is significantly increasing as the populations in many countries age. Although elderly patients with pneumonia are at risk of developing urinary tract infections, no studies have examined the prevalence or the prognostic impact of this complication. The aim of the present study was to investigate the prevalence of comorbid bacterial pyuria and the impact on the prognosis of elderly patients with pneumonia. Methods We retrospectively evaluated 132 patients aged >65 years who were hospitalized for pneumonia and who underwent a urinary sediment test on admission. The background characteristics, laboratory results and treatment regimens were documented, and the risk factors for the complication of bacterial pyuria and its association with 90‐day mortality in pneumonia patients were elucidated. Results A total of 37 (28%) of 132 patients were complicated by bacterial pyuria. The patients with bacterial pyuria were more often women, showed a poorer performance status, were more frequently fed by percutaneous endoscopic gastrostomy, and more frequently used diapers and/or a bladder catheter. Regarding first‐line drugs, 82.6% of the patients received beta‐lactamase inhibitors and extended‐spectrum penicillins. The use of a bladder catheter and a poor performance status were associated with bacterial pyuria. A multivariate analysis showed that a poor performance status was the only factor associated with 90‐day mortality. Conclusions Bacterial pyuria did not affect the prognosis of patients who were treated with penicillin‐based regimens. Thus, broad‐spectrum antibiotics are not necessarily required for elderly patients with pneumonia complicated by urinary tract infection. Geriatr Gerontol Int 2016; ••: ••–••.