This document summarizes a study of substance abuse, sexual behaviors, HIV/STD/HCV testing, and prevention service utilization among injection drug users in Dallas, Texas from 2005-2006. The study used respondent-driven sampling to obtain prevalence estimates among 597 injection drug users. Key findings include: most participants had unprotected sex and used drugs or alcohol before sex, though few were tested recently for STDs; using substances before sex was linked to riskier behaviors but not prevention service use; and effective prevention strategies are still needed to promote safer behaviors.