Abstract: Objective: To investigate the bacterial contamination and endotoxin in hemodialysis fluid.Methods: The levels of bacterial contamination were detected by pour plate method.The species of bacteria were evaluated by routine method and the endotoxin was detected by gel-colt assay with limulus reagents.Results: The average bacteria colony forming unit per milliliter in reverse osmosis and dialysis fluid from the dialyzer inlet,outlet,fluid A,and fluid B was 130 CFU/ml,259 CFU/ml,644 CFU/ml,13 CFU/ml,and 268 CFU/ml,respectively.The positive rate of endotoxin was 5.8 in reverse osmosis.The common isolated bacteria were Gram-negative bacilli(nonferments was main),Gram-positive bacilli and coccus.From April to October,the average number of colony exceeded the same kind of sample in the same year.Conclusions: Many factors such as the process of production,transportation and recycling use of reverse osmosis and the process of preparation and reservation of dialysis fluid may cause bacterial contamination,and is related to the seasons.Strict monitoring of dialysis fluid should be emphasized.