Results of the survey indicate that women engage in minor assaults against a partner at a slightly higher rate than men, and men engage in more severe assaults at a slightly higher rate than women, although neither of these differences are statistically significant. In addition, women strike the first blow about as often as men and are the only partner to assault the spouse in approximately one quarter of the cases. Since women produce less injury than men, women are actually the predominant victims in assault cases, thus first priority in both services for victims and primary prevention should be directed toward assaults by men. Nevertheless, assaults by women must continue to be addressed simultaneously because they are part of the larger socio-cultural pattern supporting violence such as child punishment. This paper discusses primary prevention of domestic violence in terms of the concept of assault, translation of that concept into empirical data, and gender differences in spouse assault. The implications of the findings for primary prevention of domestic assault are also examined. 69 references, 1 table.