A series of steroidal estrogen antagonists with no intrinsic estrogenicity in rat uterotrophic-antiuterotrophic tests has been discovered. The compounds are derivatives of estradiol containing amidoalkyl side chains at the 7α-position. The most potent compounds are N-n-butyl-N-methyl-11-(3,17β-dihydroxyestra-1, 3,5(10)-trien-7α-yl)undecanamide and N-2,2,3,3, 4,4,4-heptafluorobutyl-N-methyl-11-(3,17β-dihydroxyestra-1,3, 5(10)-trien-7α-yl)undecanamide. Structure activity relationships are discussed.