The potential for exposure of dialysis patients to greater levels of microbial and endotoxin contamination has increased dramatically during the last decade with the increase in reuse of hemodialyzers, and the use of bicarbonate dialysate and high flux dialysis. To help prevent pyrogenic reactions and bacteremia in hemodialysis patients caused by microbial and endotoxin contamination of hemodialysis fluids, the Association for the Advancement of Medical Instrumentation (AAMI) has promulgated standards for maximum allowable concentrations of bacteria and endotoxin in these fluids. Each dialysis center should develop microbiological and endotoxin surveillance policies and procedures for the types of hemodialysis fluids to assay, frequency and manner of sample collection, assay techniques, and methods for recording and interpreting results to ensure compliance with the AAMI standards. These necessary components of a comprehensive surveillance program are discussed in depth in this article. A safer environment will be provided for each dialysis patient if appropriate microbiological assay procedures are followed and the results are consistently within the AAMI microbiological and endotoxin standards.