Crocodilians suffer from a prevalence of 'big fish' stories and over-exaggeration. However, there is no doubt that some species of crocodiles can attain extremely large adult sizes. It's no surprise that questions over which is the largest are extremely common, and I'll try to shed some light on the answer. The largest species of crocodile in the world is generally considered to be Crocodylus porosus, the saltwater or estuarine crocodile. In fact, this is the largest living reptile in the world by overall weight.