Some individuals hospitalized for alcohol or drug detoxification leave against medical advice (AMA). We hypothesized that certain characteristics would be associated with AMA discharges. A case-control study of 1,426 hospital admissions for detoxification (representing 1,080 individuals) was conducted to compare patients leaving the hospital AMA (n=231) with a random sample of those completing detoxification (n=286). Latino ethnicity, detoxification from drugs, Friday or Saturday discharge, Medicaid or no health insurance, and not being treated by one specific attending physician were characteristics associated with an AMA discharge in a backward logistic regression model. Although 85% of the patients with all these characteristics left AMA, only one patient, without any of these five characteristics, did so. We conclude that clinicians can use certain clinical features to predict AMA discharge. Additional research could evaluate if treatment strategies that consider these ethnic and socioeconomic disparities may reduce rates of AMA discharge.