Abstract: We examined the explanations given by a sample of 1245 injecting drug users in Sydney, Australia for accepting used injection equipment. Factor analysis of these reasons revealed three dimensions of sharing: not caring when withdrawing or intoxicated, unavailability of equipment, and not seeing it as high risk or ease of injecting. The most common reasons given were difficulty in obtaining sterile equipment (73% of cases), the dangers not seeming so important when in withdrawal (40%) and sharing being something done with friends or lovers (31%). Most common reasons for not sharing were related to health issues (91% citing AIDS and 67% hepatitis). These data suggest that interventions target provision of sterile equipment, and education which highlights risk situations such as intoxication and withdrawal.