Tubulointerstitial nephritis (TIN) is a disease that affects a wide range of age groups – from young patients without comorbidities to elderly with multiple burdens of the disease. It is a diagnostic and theraupeutic challenge due to its non-specific course and etiology that’s often difficult to define. The aim of the study was to analyze the 3-year frequency of TIN and to assess the diagnostic difficulties, methods and effects of treatment based on the analysis of hospitalizations in the Department of Internal Medicine, Nephrology and Dialysis Military Institute of Medicine. The paper presents descriptions of fourteen patients diagnosed with TIN with their symptoms, treatments and results. Four patients had a kidney biopsy. Three patients needed temporary dialysis. In more than half of discussed patients kidney function has not returned to normal or to the values from before the onset of the disease.