2-Methoxy-4-nitroaniline was evaluated for mutagenicity using Salmonella typhimurium strains TA100, TA1535, TA1537 and TA98 both in the presence and absence of Aroclor induced rat liver S9 metabolic activation. Doses of 0, 0.8, 4, 20, 100, 500 and 2500 ug/plate were tested using the plate incorporation technique. The test article was non-mutagenic in the absence of activation although an increase in revertant colonies was observed in strain TA98 at the 2500 ug/plate level. In the presence of activation the test article was mutagenic in all strains, a biologically significant increase in the number of revertant colonies first observed at 20 ug/plate. Statistical analysis was either not performed or not reported.