Chronic pyelonephritis is an indolent kidney inflammation caused by bacterial infection that affects the pyelocaliceal system and renal parenchyma, which may lead to impaired kidney function. The disease is characterized by alternating episodes of exacerbation and remission. During an exacerbation period, dull pain in the lower back, fever, weakness, and frequent urination are observed. Urinalysis reveals leukocytes and bacteria. Treatment includes antibiotics selected upon pathogen sensitivity. Of key importance is the elimination of predisposing factors: kidney stone removal, restoration of ureteral patency, or reflux treatment.