In the Netherlands general practitioners act as the gatekeepers at the primary level to the more specialized and more expensive secondary health-care. As a rule, patients are required to have a referral from their general practitioners to be able to utilize these services. Not all private insurance companies, however, require a referral letter from their customers before reimbursing them for their costs or do not always exert a control whether such referral indeed had taken place. A mail-questionnaire was targeted to a specific group of 2000 privately insured patients to find out the reasons of self-referral. The findings suggest that patients self-refer to a specialist for medical complaints for which they expect to end up at the specialist anyway as they consider these problems as specific for the specialist. Complaints of patients who first visit their general practitioners, however, might be considered as less typical to the specialist. Patients who are living in relatively highly urbanized areas, who are better educated, and who expect to achieve a better quality of communication at the consultation with the specialist, more commonly skip their GPs before visiting a specialist.