Lack of medication reconciliation (MR) during transition in care is a major source to preventable, adverse drug events (PADE). At admission it is crucial that a thorough medication history is obtained in order to prevent discrepancies in the medication list. Still, discrepancies occur and one third of them have the potential to harm the patient. Systematic MR has proved to prevent PADE. The process of implementing MR is complex. Preliminary results from The Danish Safer Hospital Programme show, that comprehensive intervention is the key to success. Further research into interventions and implementation of MR in a clinical setting is needed.