Mildred Bowman and Alice Wardle, who are in their 60s, were sleeping when the heavy wood frame came away from the wall and collapsed on top of them.
The women, who were from Gateshead, Tyne and Wear, were crushed under the weight and slowly suffocated.
Police said cuts and bruises to their hands, suggest they made desperate attempts to free themselves.
A Foreign Office spokeswoman said: "I can confirm two sisters have died of asphyxiation in the Spanish resort of Benidorm.
"Post-mortems have been conducted and their next of kin informed."
Staff at the two star Levante Club Apartments found the bodies in a studio room on Thursday morning after friends reported them missing.
Mrs Wardle has two daughters, Dawn and Alison. Alison was in the resort at the time.
A MyTravel spokeswoman said: "We had an incident in Benidorm last week. Two ladies were found dead in a bed.
"The situation is being investigated and the company has moved all customers in similar rooms to other apartments or hotels in the area."Reuse content