- Full medical coverage may often result in overuse. Cost-sharing and the introduction of a co-payment have been shown to cause a reduction in the use of medical services. To assess the effects of the recently introduced co-payment for consultant specialist services on patient utilization of these services in southern Israel. Computerized utilization data on specialist services for 6 months before and 6 months after initiation of co-payment were retrieved from the database of Israel's largest health management organization. A decrease of 4.5% was found in the total number of visits to Soroka Medical Center outpatient clinics and 6.8% to community-based consultants. An increase of 20.1% was noted in the number of non-actualized visits to the outpatient clinics. A decrease of 6.2% in new visits to hospital outpatient clinics and 6.5% to community clinics was found. A logistic regression model showed that the residents of development towns and people aged 75+ and 12-34 were more likely not to keep a prescheduled appointment. After introduction of a modest co-payment, a decrease in the total number of visits to specialists with an increase in "no-shows" was observed. The logistic regression model suggests that people of lower socioeconomic status are more likely not to keep a prescheduled appointment.