For the first time, a faunal list of 89 species of Chironomidae is presented for the South of Portugal, using data from driftsamples taken in 12 rivers and streams. 35 species of Chironomidae are new for Portugal. The more important biogeographic result is the appearance of various mediterranean species -as Paramerina spec. Griechenland, Tanytarsus Pe23 Langton 1991 and Virgatanytarsus albisutus-; this last specie was not previously known from the Iberian Peninsula.