Since April 1995, patients’ right to information and the duty of the operator to obtain their consent are legally established in the ‘Medical Treatment Contract Act’. The aim of this study was to make an inventory of the number and type of information- and consent-complaints of Dutch dental patients, archived by the Dutch Dental Association in the years 1987-2000. By means of a registration form, complaints were analyzed and categorized. The results show that the number of complaints is slightly decreasing since the introduction of the ‘Medical Treatment Contract Act’. However, complaints about lack of information on the treatment and consequences of treatment significantly increased. 60% of all complaints officially dealt with is (partly) substantiated. Redressment of done injustice, sometimes combined with a warning, is the sanction most often imposed. Although a substantial minority of the complaints is not substantiated, communication problems between dentist and patient do also seem to play an important role in those complaints. It is therefore necessary that dentists will provide comprehensible information to their patients.