Study objectives: We evaluate the effect of a multifaceted intervention to decrease emergency department crowding on the incidence of return visits to the ED or a hospital ward. The intervention included increased emergency physician coverage, the designation of physician coordinators, and new hospital policies regarding laboratory, consultation, and admission procedures. Methods: The incidence of return visits within 7 days of discharge was estimated in samples from 2 populations (ie, patients discharged from the ED and patients discharged from the hospital) and during a 12-month period before and a 12-month period after the implementation of the intervention. Return visits were categorized into the following groups: (1) scheduled or not and (2) related or not to initial visit. Logistic regression was used in subsamples to assess the effect of the intervention while controlling for potential confounders. By using information from the provincial medical services database, variation between the periods before and after implementation of the intervention in the incidence of return visits to any ED was compared between the study hospital and 2 external control hospitals. Results: No difference was found in the incidence of return visits between the periods before and after implementation of the intervention, either for patients discharged from the ED (all returns: 11.0% versus 12.4%, 95% confidence interval on difference [CID] −1.5% to 4.3%; unscheduled-related returns: 6.5% versus 5.8%, 95% CID −2.8% to 1.6%) or the hospital (all returns: 6.8% versus 6.6%, 95% CID −2.5% to 2.1%; unscheduled-related returns: 4.2% versus 4.0%, 95% CID −2.0% to 1.7%). This lack of effect remained even after controlling for potential confounders. Variation between the periods before and after implementation of the intervention in the incidence of return to any ED was similar in the 3 hospitals examined. Conclusion: Our successful hospital intervention to decrease crowding reduced the mean length of stay for patients discharged from the ED from 13.8 to 5.9 hours, without resulting in increased return visits to the ED or hospital readmission. [Ann Emerg Med. 2003;41:173-185.]