Crews from Birling Gap and Newhaven assisted with the search for the animal around Seaford yesterday afternoon.
A spokesman for the coastguard said: “HM Coastguard assisted with the search for a dog that had fallen from a cliff in Seaford yesterday.
“Birling Gap and Newhaven Coastguard rescue teams arrived at the scene at around 4.30pm to conduct a search.”
The dog was not located, with its whereabouts and condition remaining unknown.
The coastguard advises people visiting the coast to stay clear of cliff edges and bases, as they are unstable and rocks can fall at any time, and to keep dogs on a lead.
If a pet falls from a cliff, people are urged not to go after them and instead call 999 and ask for the coastguard.