Due to the relatively low resistance of coliforms to chlorination when compared to resistance enteric pathogens such as viruses and protozoal cysts, a search was initiated for a new chlorine resistant bioindicator. The presently used indicator organisms and the reported chlorine resistance of wastewater organisms are reviewed. Wastewater effluents were chlorinated to a free chlorine residual and plated on various media at different temperatures. Surviving organisms were collected for further study. With this procedure the most chlorine osensitive organisms were eliminated from consideration. Pure cultures of 135 isolates were collected in this manner. A yeast and two different acid-fast bacteria were shown to be resistant to chlorination at levels considered necessary for the inactivation of pathogens, including viruses.