We developed a brief family treatment (BFT) intervention for substance abusing patients in inpatient detoxification to promote aftercare treatment post-detox. BFT consisted of meeting with the patient and a family member (spouse or parent) with whom the patient lived to review and recommend potential aftercare plans for the patient. A phone conference was used when logistics prevented an in-person family meeting. Results indicated that male substance abusing patients who received BFT (N=14), as compared with a matched treatment as usual (TAU) comparison group (N=14) that did not, showed a trend toward being more likely to enter an aftercare program and to attend more days of aftercare in the 3 months after detoxification. The magnitude of these differences favoring BFT over TAU was midway between a medium and a large effect size. Days using alcohol or drugs in the 3 months after detox were lower for treatment-exposed BFT patients who had an in-person family meeting than TAU counterparts (trend, medium effect), and for patients who entered aftercare regardless of treatment condition (significant large effect).