| Named By: | M. D. Uhen in 2005 |
| Time Period: | Late Eocene~37.2-33.9 Ma |
| Location: | Egypt, Peru - Otuma Formation, USA |
| Size: | Roughly about 8.5 meters long |
| Diet: | Carnivore/Piscivore |
| Fossil(s): | Several individuals, some from almost complete skull and post cranial skeletal remains |
| Classification: | | Chordata | Mammalia | Cetacea | Archaeoceti | Basilosauridae | |
Cynthiacetus is an extinct genus of basilosaurid early whale that lived during the Late Eocene (Bartonian-Priabonian, 40.4 to 33.9 million years ago.) Specimens have been found in the south-eastern United States, Egypt and Peru (Otuma Formation).