The incidence of bacteria isolated from calculi has been reported to be only 8–16 % in western literature.Septic events after endoscopic procedures for retrieval of renal stone are alarmingly at a rise recently. The rate of post PCNL sepsis and the organisms isolated in pre – operative urine culture of these patients does not correspond. This study puts in a sincere effort to analysethe bacterial culture and sensitivity analysis of stone fragments received during surgery.