The authors studied the influences of domains of psychosocial risk factors on needle-sharing with familiar people and with strangers in a cohort of female injecting drug users (IDUs). Subjects were 119 female IDUs, 46% of whom were HIV+. Subjects were given individually administered questionnaire interviews: Using Pearson correlation coefficients and multiple hierarchical regression analyses, the authors found that personality, family, and peer attributes related to needle-sharing in women were similar to those found in men, with certain exceptions. The role of the family, particularly the Significant Other, was more important and proximal in its effect on needle-sharing behavior in women than in men. There was a main effect as well as a mediating effect of family in women, buffering risk factors leading to needle-sharing.