Officers were called at around 9.20pm to a report of a road traffic collision involving a vehicle and a pedestrian on Ormskirk Road in Pemberton.
A silver Land Rover Freelander was travelling along Ormskirk Road towards Orrell Road when it collided with three pedestrians standing on the pavement, near to a public house. A driver failed to stop at the scene.
Emergency services attended and a woman in her 40s was taken to hospital but later died.
Two other male pedestrians suffered serious injuries.
Officers have arrested two males on suspicion of causing death by dangerous driving. They remain in custody at this time.
The scene remains closed and drivers are advised to take alternative routes.
PC Oliver Batty, from GMP’s Serious Collision Investigation Unit, said: “Our thoughts are with the woman’s family who are understandably devastated by the circumstances of how their loved one has lost their life.
“We immediately launched an investigation into the circumstances and the road has been closed for some time whilst we carried out a number of enquiries.
“We’re keen to hear from anyone who may have any information or dash-cam footage that may be able to assist with our investigation and give the woman’s family the answers they deserve.
“In particular, anyone who may have seen a silver Land Rover Freelander in the area of Ormskirk Road in the minutes leading up to this incident is urged to contact us.
“Anyone with information is asked to call 0161 856 4741