This study illustrates how a sample (n = 63) of Scottish drug-using women's patterns of injecting and needle sharing were strongly influenced by the nature and type of their sexual relationships. Our data shows that 12 out of the 13 drug-using couples were sharing needles and 33 out of 41 drug-using women who had ever been in a sexual relationship with a male injector had been predominately injected by their partner whilst in that relationship. For the most part, these women placed significant importance on and investment in their heterosexual relationships. These dynamics clearly impacted on the women's HIV risk taking and risk management and the implications of these findings are discussed.