2-Ethylhexyl Acrylate (TD 80-303, lot no. TF2-14220/0165MW) was tested for mutagenic activity at the thymidine kinase (TK) locust in Mouse Lymphoma L5178Y (TK+/-) cells both with and without Aroclor 1254-induced rat liver S-9 metabolic activation. Cells were exposed to the test compound dissolved in acetone for 4 hours at 37 deg. C in growth medium (Fischer's mouse leukemia medium supplemented with L-glutamine, sodium pyravaze and 10% (V/V) horse serum). After treatment, cells were grown for 2 days in growth medium and then seeded into growth medium containing 5-bromo-2'-deoxyurdine (100 ug/ml) and agar (0.35%) to select for TK locus mutants (TK -/-). After incubation for approximately 10 days, the mutant frequency was determined and compared to the mutation frequency of concurrent positive, negative, and solvent controls. In the absence of S-9, concentrations of 1.95 to 60.0 nl/ml (approximately 58 to 61 relative growths) did not induce reproducible increases in the mutant frequency. In the presence of S-9, the mutant frequency was significantly increased (2.2 to 4.6 time's background) after treatment with 70 to 150 nl/ml (approximately 68 to 81 relative growths). Therefore, 2-ethylhexyl acrylate is mutagenic in mouse lymphoma L5178Y cells in the presence of Aroclor 1254-induced rat liver S-9 but is not mutagenic in the absence of S-9.