Two hundred-five case histories of urosepsis have been analyzed for the recent 10 years in order to delineate diagnostic details. Urosepsis resulted from urolithiasis in 88 (42.9%), prostatic adenoma in 51 (24.9%), urologic cancer in 37 (18%) patients; other 29 patients had urologic diseases complicated by urosepsis. Difficulties with identification and size delineation of a septic focus were associated with the presence of bilateral renal involvement, lower urinary tract infections, urinary reflux and posttransplantation immunosuppressive therapy which reversed classic inflammatory symptoms. Extreme clinical variability of urosepsis often resulted in a delayed or premature diagnosis. Diagnostically revealing studies were sonography and computer tomography. Additional use of blood culture for bacteroides and L-bacteria, immune and biochemical tests, including total polyamine concentration, urea/creatinine ratio and leukocyte toxemic index provided an accurate diagnosis of urosepsis. These studies are essential in older patients and those with urinary disease and urologic cancers since urosepsis is diagnostically elusive in this population.