An annotated floristic catalogue is provided for the islands Chrisi (Gaidouronisi), Koufonisi and the nearby islets Mikronisi, Strongili, Makrouli and Trachilos, all off SE Kriti. Critical use is made of literature data, and hitherto unpublished records, mostly from 1997 through 2000, add substantially to the first full vascular plant inventory of the islands. The total numbers of vascular plant taxa currently known from each island are as follows (accepted taxon records from literature, if extant, in brackets): Chrisi 275 (162), Mikronisi 71 (21), Koufonisi 273 (71), Strongili 110, Makrouli 115, Trachilos 96. Most noteworthy are Suaeda palaestina and Ononis vaginalis (currently with their single localities in Europe); Allium brachyspathum, Astragalus boeticus, A. peregrinus, Galium recurvum, Hippocrepis unisiliquosa, Lagurus ovatus subsp. nanus, Ononis diffusa, Orobanche grisebachii, Schoenoplectus litoralis (new records or confirmations for the Cretan area as a whole, or for the territory of Kriti proper including offshore islands); and Chlamydophora tridentata, Frankenia corymbosa and Hymenolobus procumbens (new regional records for the E part of Kriti and its offshore islands). The N African, pronouncedly thermophilous phytogeographical element is fairly well represented in the investigated area, thence Koufonisi in particular must be considered the driest and hottest SE European island. The principal habitats encountered in each of the islands are outlined and the present conditions for nature conservation discussed.