Calyceal diverticular stones are rare clinical entities without a clearly defined consensus on the treatment. Treatment indicationsinclude recurrent urinary tract infections, chronic pain and renal impairment. Treatment modality of surgical approach is usuallybased on the location of calyceal diverticulum.A 23-year-old woman was presented with a calyceal diverticular stone of 16.5 mm. Her medical history revealed multiple urinary tractinfections caused by extended spectrum beta-lactamase (ESBL)-producing Escherichia coli of which the stone was predicted to be thereason. The patient was treated ureterorenoscopically, a decision of which was taken intra-operatively.In conclusion, insisting on performing nephroscopy following an intra-operative retrograde pyelography revealed no apparentostium which could be interpreted as ureterorenoscopic retriaval would fail and development of postoperative bacteremia despite allprecautions taken pre-and intra-operatively were two lessons indicating that all efforts must be exercised to reach the most minimalinvasive method for the treatment of calyceal diverticular stones.