With the aim of examining predictors of social workers’ ideal recommendations of inpatient or outpatient treatment for problem substance users, this study applied multilevel logistic regression to factorial survey data collected from a sample of 205 frontline social workers from 36 social services units in Sweden. The results show that social workers’ ideal recommendations of inpatient or outpatient treatment are based on evaluations of a number of client characteristics. These include the clients’ treatment preferences, their primary drug, levels of social resources, and age. In addition, it was found that professional recommendations are also determined by treatment availability and policy guidelines, and by the decision makers’ own ideological convictions regarding alcohol and narcotics problems. This study brings to light the necessity of organizational routines that allow and encourage social workers to reflect on and to articulate their judgements and decisions.