Non-attendance is claimed to waste substantial health care resources. However, this is only vaguely supported by empirical evidence. The epidemiology of non-attendees is explored in a rather large number of studies along with a sizeable number of studies documenting the effectiveness of various interventions to reduce non-attendance rates. Very few studies include more than one intervention and very few report information on the cost of the intervention which enables only vague conclusions about the cost-effectiveness of the interventions. The effectiveness of charging a fine on non-attendees, which has recently been suggested in Denmark and United Kingdom, has been studied in very few studies. These studies reveal that a fine will as most economists expected reduce the non-attendance rate. The literature of non-attendance discloses an immense need for studies addressing the non-attendance problem applying economic theory and standards of analysis.