ABSTRACT. The purpose of this study is to present a thematic and etymological glossary of aquatic and bird genera names which have been mentioned in Iranian Bundahišn. In this research, after arranging animal names in Persian alphabetic order in their respective genus, first the transliteration and transcription of animal names in middle Persian language are provided. Afterwards, the part of Bundahišn that contains the actual animal names and the relevant translations are mentioned. The etymology of every animal name is described by considering the morphemic source. Finally, mention is made of the mythology connected to the animal and the animal category in Iranian Bundahišn (if available), and the way in which the words have changed from Old Persian up to now. Changes in the name of every animal from the ancient languages such as Indo-European, Sanskrit, Old Persian and Avestan to middle languages such as Pahlavi, Sogdian, Khotanese, and Chorasmian and how the name appears in new Iranian languages and dialects such as Behdini (Gabri), Kurdi, Baluchi and Yaghnobi are also referred to.