- The condition where someone has physical symptoms for a number of weeks for which no clear somatic cause can be found, is known as medically unexplained symptoms (MUS).- In this article we give an overview of current insights into the prognosis of MUS.- Extensive somatic testing in patients diagnosed with MUS by a physician, rarely results in a somatic diagnosis.- In approximately half of these patients, MUS disappear spontaneously within one year.- Symptom-related characteristics - such as experiencing multiple physical symptoms simultaneously-, and psychological characteristics - such as unhelpful thoughts - are predictors of an unfavourable prognosis for MUS.- Close monitoring of patients with MUS enables timely interventions, and may help to prevent MUS following an unfavourable course. Existing guidelines may help in choosing treatment and tailoring it to the individual patient.