Background and AimsScreening, brief intervention and referral to treatment' programs have been promoted widely as US federal policy. Little is known about the efficacy of the RT component (referral to treatment) of brief intervention for motivating patients with unhealthy drug use identified by screening to use addiction treatment. This study aimed to compare receipt of addiction treatment following two types of brief intervention for drug use versus a no-intervention control group among primary care patients screening positive for drug use. DesignSecondary analyses from a single-site randomized controlled trial. SettingMassachusetts, USA. ParticipantsA total of 528 adults with Alcohol, Smoking and Substance Involvement Screening Test (ASSIST) drug-specific scores 4. InterventionsRandom assignment to: (1) a 10-15-minute brief negotiated interview (BNI) conducted by health educators (n=174), (2) a 30-45-minute adaptation of motivational interviewing by Masters-level counselors (MOTIV) (n=177) or (3) no BI (n=177). All received a list of treatment and mutual help resources; both intervention protocols included dedicated staff for treatment referrals. MeasurementsReceipt of any addiction treatment within 6months after study entry, assessed in a state-wide database and hospital electronic medical record linked to trial data. FindingsAmong 528 participants, the main drugs used were marijuana (63%), cocaine (19%) and opioids (17%); 46% met past-year drug dependence criteria (short form Composite International Diagnostic Interview); and 10% of MOTIV, 18% of BNI and 17% of control participants had any addiction treatment receipt within 6months after study entry. There was no significant difference in addiction treatment receipt for BNI versus control [adjusted odds ratio (AOR)=1.11; 95% confidence interval (CI)=0.57, 2.15, Hochberg adjusted P=0.76]. The MOTIV group had lower odds of linking to treatment (AOR=0.36, 95% CI=0.17, 0.78, Hochberg adjusted P=0.02) compared with the no BI group. ConclusionBrief intervention delivered in primary care for screen-identified drug use did not increase addiction treatment receipt significantly; a motivational interviewing approach appeared to be counterproductive.