Data came from interviews with 2,143 couples, of whom 1,146 had one or more children aged 3 to 17 years old living at home at the time of the interview. A series of questions called the Conflict Tactics Scale measured violence and incidence of violence within the preceeding 12 months and during the duration of the marriage or the lifetime of the children. The interviews took place between January and April 1976. A total of 58 percent of the respondents had used some form of violence toward their child during the current year; 71 percent had done so at some time. Over four-fifths of the 3- and 4-year-olds and 5- to 9-year-olds had been hit during the survey year. Two thirds of the children aged 10 to 14 and one third of those aged 15 to 17 had been hit during the year. About 3 percent of the children were kicked, bitten, or punched by their parents in the year; just over 1 percent had been beaten during the year. One child in 1,000 faced a parent who threatened to use a gun or knife during the year. The extreme forms of parental violence occurred regularly; they were not isolated events. The data suggested that from 1.4 to 1.9 million children in the United States were vulnerable to physical injury from their parents during the year, a figure at least 1.2 million higher than previous estimates. Violence peaked at ages 3 to 4 and 15 to 17. Boys were slightly more likely than girls to be targets of physical violence. In one of six couples a spouse had engaged in violence toward the mate during the survey year. The parent's own abuse as a child, lower socioeconomic status, unemployment, stress in middle-income families, a family size of two children, and social isolation were all associated with higher levels of violence. Cultural norms supporting violence unless there is an injury was also undoubtedly a factor. Because other organizations with high levels of conflict rarely experience physical violence, factors in addition to the high level of conflict are involved when considering violence in family conflict. Notes and 53 references are supplied.