The adult male rider suffered broken legs in the incident on busy Golden Way, Penwortham.
The accident involving a Triumph Tiger motorcycle and a Dacia Sandero, on the southbound carriageway between Middlesforth and Booths roundabouts, happened at around 5.30pm.
Police closed the road and are still at the scene.
The road is likely to be closed for about another hour, said police.
A spokesperson for Lancashire Police said; “There was a road traffic accident involving a car and a motorcyclist.
“The motorcyclist received significant injuries, broken legs, but they are not life threatening.”