The study was carried out to evaluate the radical scavenging activity, and antimutagenic and anticancer effects in Korean soybean paste(doenjang) added with various mushrooms. Ganoderma lucidum doenjang(Gl-TD) showed significant inhibitory activity against the 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical, with an IC50 value of 245㎍/㎖. In contrast, the other doenjang varieties appeared to have weaker antioxidant activity. Four kinds of doenjang didn`t have any antimutagenic activity against N-methyl-N`-nitro-N-nitrosoguanidine(MNNG) by adding of 5mg/plate, but exhibited a strong inhibitory effect(55~70%) against aflatoxin B1(AFBI). Especially Phellinus linteus doenjang(Pl-TD) inhibited more than 70% of the mutagenicity induced by AFBI in Salmonella typhimurium TA100. On the other hand, the mushroom doenjang varieties showed relatively weak activity toward MNNG in SOS chromotest, their inhibitory rate ranging from 23% to 33%. Methanol extracts of Gl-TD and Pl-TD inhibited by 91%~92% the growth of AGS gastric cancer cells in a concentration of 100㎍/㎖.