This study attempted to replicate and extend the findings of Johnson (1999) that there are two distinct subgroups of physical aggression within relationships: intimate terrorism (IT) and common couple violence (CCV). Johnson suggested that the existence of subgroups might help to reconcile the apparently conflicting findings of feminists and family violence perspective research by challenging the belief in a monolithic model of relationship aggression. Frequency analysis in the current study showed broad support for Johnson's findings: qualitatively different types of physically aggressive relationships exist. The first type is controlling aggression (CA); the motivation behind the use of this type of physical aggression is to maintain overall control over one's relationship. The second type of physical aggression is noncontrolling aggression (NCA), which in contrast to CA, represents a reaction to the particular stressors. Physical aggression was found among both high and low controllers; high controllers were far more likely to also use physical aggression than were low controllers. This relationship between controlling aggression supports both feminists and evolutionary perspectives that conceptualize aggression as a coercion tactic. Intimate terrorism (IT) was found to be, as expected, primarily male, whereas violent resistance (VR) was clearly female. The dynamics of relationships in which only one person uses physical aggression, even if it does not appear to be control-oriented, may well differ in important ways from truly bidirectional physical aggression. Further research that uses both quantitative and qualitative methods is needed to shed light on these relationships. The participants were drawn from a female shelter sample consisting of 43 female participants who were all current residents in Women’s Aid domestic violence shelters, 4 men who were attending a male treatment program for domestic violence, and a male prisoner sample consisting of 97 inmates from prisons in the north of England. Tables, appendixes A-B, references