A 41-year-old man and a 68-year-old woman were both pronounced dead at the scene after the accident on the A6094 road shortly before 1pm on Sunday.
A stretch of the road between Leadburn and Howgate was closed for six hours after the incident, which happened near to the Leadburn Inn, to allow Police Scotland to carry out investigations.
Officers are now appealing for anyone who saw either of the vehicles involved - a silver Vauxhall Zafira and a red Honda Jazz - prior to the crash.
Sergeant Ross Drummond, of Police Scotland’s road policing unit in Dalkeith, said: “My thoughts and condolences are today with the loved ones of both drivers at this difficult time.
“A thorough investigation is now under way into the full circumstances and I wish to take this opportunity to thank the Scottish Fire and Rescue Service, the Scottish Ambulance Service and everyone who assisted in the immediate aftermath of this collision.”
While he said there were no known eyewitnesses to the crash, Mr Drummond added: “There were several members of the public who we understand stopped to help and left the scene before speaking with police.
“I would encourage them to come forward even if they didn’t see the collision itself but offered some assistance.”