Inpatient withdrawal treatment (detoxification) is common in opioid dependence, although dropout against medical advice often limits its outcome. This study aimed to assess baseline predictors of dropout from inpatient opioid detoxification with buprenorphine, including age, gender, current substance use, and type of postdetoxification planning. A retrospective hospital chart review was carried out for inpatient standard opioid detoxifications using buprenorphine taper, in a detoxification ward in Malmö, Sweden (N = 122). Thirty-four percent of patients (n = 42) dropped out against medical advice. In multivariate logistic regression, dropout was significantly associated with younger age (OR 0.93 [0.89-0.97]) and negatively predicted by inpatient postdetoxification plan (OR 0.41 [0.18-0.94]), thus favouring an inpatient plan as opposed to outpatient treatment while residing at home. Dropout was unrelated to baseline urine toxicology. In opioid detoxification, patients may benefit from a higher degree of postdetoxification planning, including transition to residential treatment, in order to increase the likelihood of a successful detoxification and treatment entry. Young opioid-dependent patients may need particular attention in the planning of detoxification.