bObjectives: Analyse the failure cases that have to converse to open surgery in Percutaneous Nephrolithotomy (PCNL) technique in order to contribute the experiences to the PCNL approachMethods: Prospective, descriptive study analyses 10 failure cases that have to converse to open surgery among 175 cases of PCNL in Binh Dan Hospital from December 2005 to December 2007.