17-${eta}$-hydroxysteroid dehydrogenase type 1 ($17{eta}$-HSD type 1) mediates the reaction of $17{eta}$-estradiol (E2) production from estrone (E1). Inhibitory effects of curcuminoids on $17{eta}$-HSD type 1 activity were investigated to find a lead compound for treating estrogen-dependent diseases including breast cancer. Among curcuminoids, demethoxycurcumin showed potent inhibitory effect ($IC_{50}=2.7{mu}M$) on mouse $17{eta}$-HSD type 1. Curcuminoids also displayed their inhibitory effects on the production of $17{alpha}$-estradiol which is a carcinogenic metabolite produced by the enzyme. Bisdemethoxycurcumin ($IC_{50}=1.3{mu}M$) showed potent inhibitory effect on the $17{alpha}$-estradiol production by chicken $17{eta}$-HSD type 1. Curcuminoids did not inhibit ERE transcriptional activity with and without E2. Taken together, curcuminoids can be used for treating and preventing E2-dependent diseases via inhibition on $17{eta}$-HSD type 1 activity.