The examination of police response to domestic violence encompassed 24 police departments across the Commonwealth. Data were collected over 3 months and focused on specific incidents of domestic violence. Interviews with police officers and staffs of women's shelters provided additional information. The study addressed four issues. One was the extent to which the new standards for arrest of domestic- violence offenders have been followed by police officers. Another is the new law's effect on statewide policing patterns. A third is the nature of the issues that should be considered when interpreting domestic violence statistics in a mandatory arrest context. A fourth issue is the extent to which there have been arrests of both offenders and victims. The study found that training, information, and policies for changes in the domestic violence statute have been widely implemented. There has also been a significant increase in the arrest of perpetrators, especially those who violate court protection orders. There is still a significant variation in the extent of arrests among departments. All the departments in the study have implemented new, approved policies regarding responses to domestic violence. 9 tables and 26 references