The crash at around 4pm on the northbound carriageway, between junctions 32 and 33, led to the motorway being closed for nine hours.
Police, ambulance and fire crews responded where they sadly found the driver and front seat passenger dead at the scene.
Lancashire Police say their next of kin are being informed. No further details on the casualties have been released at this stage.
The northbound carriageway remained closed for several hours whilst collision investigators examined the scene, before reopening shortly before 1am today.
Large screens were placed around the stricken vehicle whilst northbound traffic was held.
Highways later removed a section of the central reservation barrier to release 7 miles of trapped northbound traffic, with motorists joining the southbound carriageway to resume their journeys.
A spokesman for Lancashire Police said: "We were called at around 4pm to reports of a collision on the M6 motorway between junction 32 and 33.
"Officers attended and sadly two people, the driver of the vehicle and the front seat passenger, were pronounced dead at the scene.
"Their next of kin are being informed and our thoughts remain with them at this time.
"Anyone who witnesses the incident is asked to contact us on 101 quoting log number 1125 of August 13."
Three fire engines were also deployed to help make the scene safe for police and ambulance crews.
A fire service spokesman added: "We were called at 4.21pm to reports of a road traffic collision on the M6 motorway, northbound carriageway between junction 32 and 33.
"Three fire crews, from Preston, Fulwood and Lancaster attended and assisted in making the scene safe."