Four new species of littoral sponges (0-150 m) are described from the Balearic islands (Western Mediterranean): Axinella pseudominuta, Spongosorites cavernicola, Topsentia garciae, Scopalina azurea. Four species are recorded for the first time in the Mediterranean Sea: Rhabderemia ucanthostyla, Phorbas dendyi, Plocamione dirrhopalina, Microciona tenuissima. Ten poorly known species are redescribed and illustrated: Prosuberites rugosus, Ceratopsion minor, Bubaris subtyla, Rabdoploca curvispiculifera, Hymerhabdia oxytrunca, Rhabdeurypon spinosum, Raphisia spelea, Haliclona subtilis, Reniera valliculata, Rizoniera rhizopora. The geographic and bathymetric distribution of these species is also provided and some of their taxonomical features discussed.