Introduction: Suprapubic catheter (SPC) and bladder indwelling catheter (BIC) placement are among the most common urological procedures. Inadvertent misplacement of the catheter tip into the ureteral orifice is an infrequent event with potentially critical complications. Case Presentation: We describe two cases of inadvertent intraureteral misplacement of an SPC and a BIC. A 66-year-old man with chronic kidney disease (CKD) stage G3b, urethral stenosis, long-term SPC who attended the emergency room (ER) 6 hours after the last catheter replacement due to low back pain, fever, deterioration of the general condition, anuria, acute kidney injury (AKI); CT-scan revealed a left uretero-hydronephrosis secondary to obstruction of the catheter balloon misplaced inside the distal ureter. A 59-year-old woman with CKD stage G3b, post-radiotherapy cystitis, and small capacity bladder, long-term BIC who attended the ER a few hours after the last BIC replacement due to abdominal pain, anuria, AKI; CT-scan revealed left hydronephrosis secondary to catheter obstruction within the distal ureter. In both patients, management was conservative, consisting of removing the catheter and repositioning it inside the bladder, in addition to hydration and antibiotherapy. Conclusions: These cases illustrate that awareness of this rare complication can be prevented by confirming the correct positioning of SPC or BIC after its replacement. Early detection and management of this complication can prevent a serious clinical setting.