The man, in his 50s, and a woman, in her 30s, were taken to hospital after a smash between a BMW and their Mini in Parklands at 1pm on Monday.
An Essex Police spokesman has confirmed on Tuesday the two people died from their injuries.
He said: “We are now able to confirm two people have died after being involved in a collision in Parklands, Waltham Abbey, Monday afternoon.
“We were called to reports of a collision between a BMW and a Mini near to the junction with Congreve Road shortly before 1pm.
“We can now confirm the occupants of the Mini, a man aged in his 50s and a woman aged in her 30s, have died from their injuries.
“We continue to appeal for anyone who either witnessed the incident or recorded it on dashcam to come forward and speak to us if they have not already done so.”
Anyone with information should submit a report online or use the ‘live chat’ function on that page, which is available between 7am and 11pm.
You can also call 101 and cite incident 481 of January 10.