This study used two waves of the National Survey of Families and Households (1987 to 1988 and 1992 to 1994) to examine the effect of the transition to parenthood on the division of labor among married couples, hypothesizing that parenthood would produce a more differentiated gender division of labor, but that attitudes and preparental division of labor would moderate parenthood. There were no effects of parenthood nor direct or moderating effects of gender attitudes on husbands' employment or housework hours, with the exception that fathering more than one child results in slightly longer employment hours. Motherhood increases wives' housework hours and reduces employment hours. Wives' traditional gender attitudes reduce their employment, but not their housework. Women married to full-time breadwinners have the largest reductions in employment after motherhood. Last, wives' initial economic dependency increases wives' subsequent housework and husbands' employment. Parenthood crystallizes a gendered division of labor, largely by reshaping wives', not husbands', routine.