To evaluate cases with unclassified multiple congenital abnormalities including microtia and anotia as component congenital abnormalities in order to reveal the characteristic pattern of other associated component congenital abnormalities and to make an attempt to establish a registry diagnosis on the pattern of associated congenital abnormalities and to stimulate the establishment of an international registry of cases with unclassified multiple congenital abnormalities comprising of microtia and anotia. Methods: The large population-based dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980–1996. Results: A total of 156 cases with unclassified multiple congenital abnormalities including microtia and anotia were analyzed according to the number of 2–9 component congenital abnormalities. The comparison of the distribution and frequency of component congenital abnormalities in these cases showed significant differences from the data of other unclassified multiple congenital abnormalities. Of the 156 cases, registry diagnosis was possible in 48 (30.8%) cases. Conclusions: The evaluation of available dataset of unclassified multiple anotia and microtia may help the delineation of new syndromes and associations with better prognosis and recurrence risk estimation, thus finally a better chance for their prevention. Orv. Hetil., 2011, 152, 1399–1416.