This paper investigates domains of drug injection behavior and the association of derived factors to HIV serostatus. Two sets of data were randomly selected and matched from a national data set of over 40,000 drug injectors. One set was HIV seropositive and the other HIV seronegative heterosexual injectors. Samples were matched to control for the effects of race/ethnicity, gender, and age on serostatus. Factor analysis was used to investigate relationships among drug injection behaviors. Four independent factors were found. Two factors were found to be statistically related to HIV serostatus in high seroprevalence areas. None of the needle use factors was found to be significantly associated with serostatus in low seroprevalence areas.