Information used in this study was obtained from a database of clients presenting for assessment and/or treatment to a hospital-based sexual assault care center in a metropolitan area in Ontario, Canada, between the years 1992 and 1999. Information used in the study was obtained from the center's database. Data were collected on client characteristics, presentation and service delivery characteristics, coercion, and physical injuries. Variables related to coercion included the use of verbal threats, alcohol and drugs, physical restraint, assault while sleeping, physical violence, and the use of a weapon. A mean severity-of-coercion index was developed in collaboration with 10 experts working in the area of sexual assault. The findings show that women assaulted by spouses reported for treatment sooner than other groups of women and were more likely to call the police. Although assaults committed by spouse and boyfriend assailants were generally more physically violent and resulted in more victim injury than assaults by acquaintances, an overall linear relationship between variables and the degree of victim-perpetrator familiarity was not found. These results challenge the persistent stereotypes that suggest spousal sexual assaults are less serious and less violent than those by other perpetrators who knew their victims. 4 tables and 18 references