A sample of 6,029 married persons from the National Survey of Families and Households was analyzed to determine the correlates of sexual inactivity in marriage and to see if sexually inactive marriages were less happy and stable than those with sexual activity. Sixteen percent of the marriages in this sample had been sexually inactive during the month prior to the interview. A logistic regression analysis showed unhappiness with the marital relationship, increased likelihood of separation, lack of shared activity, few arguments over sex, lack of physical violence, increased age, fewer children, the presence of preschoolers, and poor health all to be significant correlates of sexually inactive marriage. Significant differences existed between males and females, such as the presence of relationship violence being associated with sexual activity only for females, and the presence of preschoolers and poor health associated with sexual inactivity only for males. These findings suggest that although sexually inactive marriages are not uncommon, they are not happy, stable marriages in which the partners simply do not have sex. Lack of sexual activity may be a danger signal for many marriages.