Diagnosis of tubulointerstitial nephritis in the course of acute intermittent porphyria is rare. The paper presents a case of a 29‑year‑old female. Initially she presented with acute pain in the hypogastric region, polyuria and dysuria, no fever. She was initially treated for urinary tract infection. The pain intensified and was accompanied by paraesthesia of upper and lower extremities with hyperesthesia, through increasing pain and muscle weakness to quadriparesis. Tetany and epileptic seizure occurred. Laboratory results revealed elevated inflammatory markers, signs of kidney failure, severe electrolyte imbalance: hyponatremia, hypokalaemia and hypocalcaemia. Blood and urine culture revealed growth of Klebsiella pneumoniae (ESBL+), which was treated with meropenem. Analysis of daily urine output suggested loss of sodium, potassium and calcium ions to be of renal origin. Because of red‑brown urine colour, acute intermittent porphyria (AIP) was considered. Level of delta aminolevulinic acid in urine and fluorescence spectre of plasma porphyrin were assessed and patient was diagnosed with acute intermittent porphyria with acute tubulointerstitial nephritis.