During investigations in the southern part of South Tyrol, called Unterland in 2004,134 gall midge species were found at 18 localities situated at altitudes from 250 m up to 2340 m a.s.l. A total of 10 species are new records for the fauna of Italy (Contarinia fagi, C. steini, Dasineura interbracta, D. spicatae, Gephyraulus raphanistri, G. sisymbrii, Macrolabis achilleae, M. laserpitii, Mycodiplosis saundersi and Oligotrophus schmidti). Additionally 12 species are new records for South Tyrol (Aschistonyx carpinicolus, Asphondylia ononidis, Contarinia quercina, Dasineurafilicina, D. gleditchiae, D. papaveris, D. sisymbrii, Janetiella oenephila, Mikomya coryli, Obolodiplosis robiniae, Ozirhincus millefolii und Phegomyiafagicola). The present gall midge fauna of South Tyrol includes 230 species. An annotated list of species found in South Tyrol in 2004 is given with details of collection sites as well as biological data. The gall midges are associated with 95 host plant species. The average species number per individual locality (17 species, from 4 to 29) is relatively high. The number of gall midge species decreases with increasing altitude. The majority of species were found at one to three localities. The following species occur abundantly: Wachtliella rosarum on Rosa canina and related species of Rosa and Cystiphora taraxaci on Taraxacton officinale, A total of 78 species have european, 48 euro-siberian and 6 submediterranean distribution. Dasineura gleditchiae on Gleditschia triacanthos and Obolodiplosis robiniae on Robinia pseudoacacia are nearctic species which have been accidentally introduced from North America to Europe and were recorded in South Tyrol in 2004 for the first time. Galls of Janetiella oenephila on leaves of Vitis vinifera were also recorded for the first time in South Tyrol. A total of 15 gall midge species are associated with 13 alpine and subalpine host plant species. Dasineura spicatae (KIEFFER, 1909) is a valid name (not a synonym of Jaapiella veronicae) for a species which causes galls on Veronica spicata.