A woman who checked into a hotel room in Gateshead said she found the words "I'm going to rape you" on the TV screen.
She was staying at the Whitemare Pool Travelodge hotel, on Wednesday, when she found the message.
The hotel removed the words, apologised and gave her a refund when she informed staff.
Travelodge said it believed someone may have used the TV manufacturer's code to change the settings.
A spokesperson said there was not usually any sort of message on the hotel's TV screens.
The woman, who does not want to be identified, said Travelodge had been "great about it".
In a statement, a Travelodge spokesperson said: "We have already been in contact with the customer involved and apologised that such a message could appear."
The hotel chain said it took the incident "very seriously" and had "launched a full investigation with our television supplier".
The police are not currently involved in the inquiry, Travelodge said.