Officers from Kent Police were called to the southbound carriageway of the A249 at its intersection with Key Street at 11:59 p.m. on Tuesday, June 28, 2022.
South East Coast Ambulance Service and Kent Fire and Rescue Service were also called to the scene, where a man is said to have fallen onto the carriageway and been hit by a lorry.
He was pronounced dead at the scene, and a report for the coroner will be prepared.
Officers want to hear from anyone who was on the A249 near Sittingbourne or in the vicinity of the Key Street roundabout at the time of the incident.
They’re also asking drivers with dashcams to look for footage that could help their investigation.
Anyone with information should contact Kent Police at 01795 419119 and reference 28-1562.