The kidneys of the patients with purulent pyelonephritis (PP) undergo anatomic and functional alterations. The latter may be irreversible in some cases. The severity of the above alterations depends on PP form, choice and time of treatment. Our study included 84 patients who had PP at the age of 15 to 70 years. Primary PP was detected in 47 (56%) patients, secondary--in 37 (44%) patients. Open surgery was performed in 18 patients (group 1), transcutaneous drainage was used in 38 patients (group 2), conservative treatment was conducted in 28 patients (group 3). Comparison of dynamic nephroscintigraphic findings showed that recovery of renal function in groups 2 and 3 lasted 6-12 months versus 60-84 months in group 1. The degree of the renal function recovery depends on the PP form, age of the patient, duration of the disease, virulence of the causing agent, comorbid pathology, immune status, method of treatment. This was confirmed by the data of complex radionuclide examination. Long term complications, for instance, progress of arterial hypertension (41% cases) and chronic pyelonephritis (44% cases) were observed more frequently and earlier in patients after open operations.