Three generations of a kindred comprising 50 individuals are described in which recurrent intrahepatic cholestasis of pregnancy has occurred with high frequency. A uniform expression and complete penetrance of the trait in the women of a limited "affected" portion of the kindred (6 affected of 10 women), along with the direct parent-to-child inheritance mode, supports the conclusion that the inheritance mode is Mendelian dominant in type. Male expression of the phenotype seems to be inhibited. This is derived from observations that unmasking of carriers in the kindred by normal challenge provided useful information only in women, and was unhelpful when applied to a male obligate carrier. A linkage analysis is presented that explores the possibility of a relationship between the syndrome and homologous leukocyte antibody histocompatibility antigens. On the basis of present data, no conclusion can presently be reached regarding this possibility.