We present an updated list of the vascular flora of the island of Montecristo (Tuscan Archipelago, Italy), which was last described in 1976 by Paoli and Romagnoli. The inventory has been updated based on a comprehensive bibliographical review of floristic floras and previous inventories, together with the revision of herbarium specimens already preserved in Tuscan herbaria and the implementation of survey campaigns carried out on the island between 2011 and 2024. The inventory counts 585 specific and subspecific taxa currently present on the island (including 518 spontaneous entities and 67 cultivated ones), the highest number of species ever recorded on the island. Since 2000, 71 new species have been confirmed, 43 of which are new to Montecristo Island. In addition, 28 species have been re-confirmed since the last records in 1903 or 1864. We excluded 14 taxa, 8 of which were the result of a revision of the herbarium material, which led to the correction of previous erroneous determinations or due to the description of new taxa, such as Saxifraga montis-christi Mannocci, Ferretti, Mazzoncini & Viciani. The characterisation of the flora of Montecristo is consistent with the Mediterranean climate of the island in terms of life forms and chorotypes. The analysis showed that the main geographical distribution elements are Eurosiberian-Mediterranean and Mediterranean species, while the predominant life form is the therophyte. From a floristic point of view, Montecristo is the poorest island in terms of species and has the highest amount of endemism in relation to its area.