This study was conducted to evaluate the mutagenic potential of polydimethylsiloxane (PDMS) fluid (2 and 50 cs.). The test materials were evaluated in Salmonella typhimurium (TA 1535, TA 1537, TA 1538, TA 98, and TA 100) using the Ames assay in the presence and absence of Aroclor induced rat liver enzymes. Dilutions of the test substance were made using deionized water, absolute ethanol, or dimethylsulfoxide (DMSO). The first phase of the study was the spot plate test in which 10 uL of the test substance/plate was spotted directly on cultures containing the microorganisms, with and without activation, and incubated for 48 hours. In the second phase, concentrations of 0 (solvent control), 0.5, 5, 100, or 500 uL of the test substance, or a positive controls, were plated with each tester strain, in presence and absence of microsomal enzymes, and incubated for 48 hours. Sodium azide, 9 amino acridine, 2 nitrofluorene, and 2 anthramine served as positive controls. All the plates were evaluated and compared with positive and negative controls. Under the conditions of this study, the test substances failed to exhibit mutagenic activity both with and without activation.