The flora and vegetation of the north-easternmost islands of the prefecture of Dodekanisos, Agathonisi and Pharmakonisi, which remained floristically almost unexplored until recently, have been investigated. Included are also the flora and vegetation of the seven islets around Agathonisi. Altogether, 402 species and infraspecific taxa of higher plants belonging to 131 genera and 52 families have been found. The analysis of the flora and the classification of the taxa into three main chorological units and five life form types shows that the Mediterranean elements and the therophytes predominate. A comparison of the individual floras of the two islands and seven islets revealed very low values of Sørensen's similarity coefficient, indicating a remarkable floristic independence. This floristic independence is also expressed by the fact that the nine islands and islets have not one taxon in common, whereas 130 taxa occur only on one island or islet each. Three vegetation zones (littoral, epilittoral and interior) are distinguished and described. The vegetation physiognomy differs from islet to islet due to different dominant species. Human activities such as agriculture, grazing, fires, etc. likewise affect the local floristic composition and vegetation physiognomy.