The objectives of this study were to screen the effect of different clinoptilolite compounds on S. typhimurium survival and to compare the most effective compounds as amendments using agricultural soil and aqueous microcosm conditions. These microcosms were inoculated with the bacterial culture and at periodic intervals (over 12-30 days) viable Salmonella populations were enumerated using selective media. In screening studies Salmonella populations were found to be lower from the smaller mesh clinoptilolite compounds than from wood-chip sources or larger mesh clinoptilolite compounds at the end of 14 days. However the response was highly correlated with the change in moisture content. In soil microcosm studies where moisture content was kept constant, there was an overall reduction of about 4 log units bur there was no significant difference between the unamended control and the treatments. When smaller mesh clinoptilolites were evaluated in phosphate saline buffer there was a significantly lower (P<0.05) number of viable S. typhimurium than in the unamended treatments. However, when the clinoptilolite compounds were sterilized prior to use, if was observed that the bacterial populations were protected from viability loss when compared with the unamended control.