This randomized, controlled trial, conducted among out-of-treatment heroin/cocaine users at an emergency department visit, tests the impact on sexual risk of adding brief motivational intervention (B-MI) to point-of-service testing, counseling and drug treatment referral. 1,030 enrollees aged 18-54 received either voluntary counseling/testing (VC/T) with drug treatment referral, or VC/T, referral, and B-MI, delivered by an outreach worker. We measured number and proportion of non-protected sex acts (last 30 days) at 6 and 12 months (n = 802). At baseline, 70% of past-30-days sex acts were non-protected; 35% of sex acts occurred while high; 64% of sexual acts involved main, 24% casual and 12% transactional sex partners; 1.7% tested positive for an STI, and 8.8% for HIV. At six or 12 month follow-up, 20 enrollees tested positive for Chlamydia and/or Gonorrhea, and 6 enrollees HIV sero-converted. Self-reported high-risk behaviors declined in both groups with no significant between-group differences in behaviors or STI/HIV incidence.