The flora and fauna of Nisyros presents great interest both because of its volcanic nature and also its geographic position on the immigration routes of the Asian species towards southern Europe and vice versa. The documented presence of 450 species of flora, 85 species of avifauna, 7 species of reptiles, and the presence of Monachus monachus seals on its shores highlight Nisyros as a place worthy of special protection and study.

The dense bushy vegetation consisting of the thorny burnet  (Sacropoterium spinosum), the lavender (Lavandula stoechas),the hoary rock rose & Gallipoli rose (Cistus creticus & Cistus salvifolius), the thyme (Thimus capitatus), the savory (Satureja thymbra), the laurel (Daphne gnidioides), the spiny broom (Calicotome villosa), the Nisyros bellflower (Campanula nisyria) which is a unique endemic plant species, the large number of trees, oaks, olive trees, fig trees, almond trees, agramithia trees, and lemon trees, proves that Nisyros is the only "green" active volcano in the Aegean Sea.

The fauna of the island is of corresponding range and diversity. Falcons are continuously flying in the horizon, many kinds of lizards are hiding under rocks, while there are also many free-range animals such as goats, pigs and cows.