OBJECTIVES: The objectives were to find out whether hypomineral-ized permanent first molars and incisors, known as Molar Incisor Hy-pomineralization (MIH), occurs all over Europe, whether its preva-lence in each country is known and whether or not it is considered to be a clinical problem. SAMPLE AND METHODS: Clinical photos of MIH and a five-item questionnaire were sent to members of the Euro-pean Academy of Paediatric Dentistry (EAPD). A total of 59 question-naires were sent to members in 31 countries. After one month a re-minder was sent to non-responders. RESULTS: Fifty-four dentists (92%) in 30 countries (97%) returned the questionnaire. MIH was stated to occur in all but one country (the Czech Republic). Nearly all the responders (97%) stated that they were familiar with the clinical appearance of MIH and a majority saw it as a clinical problem. Fur-thermore, a large majority of the responders (90%) considered it im-portant to map the prevalence of MIH in European countries as such data are available to only a limited extent. CONCLUSION: Paediatric dentists in Europe are aware of MIH and the majority consider it to be a clinical problem. Only limited data are available on the prevalence of MIH. Comparable and representative prevalence studies are there-fore urgently needed to gain more knowledge about the magnitude of MIH and related clinical problems.