Two hundred and fifty litres of diesel valued at £247 was siphoned from the tank of a lorry parked in a Surrey lay-by while the driver slept.
Police said the driver of the Volvo lorry, which was being used to transport chemicals, had his cab curtains shut when the theft happened.
He was woken by a man who told him he thought someone had stolen his fuel on the A3 at Wisley on Thursday night.
Pc Stephen Cake said six other lorries were parked in the lay-by at the time.
'Lock fuel caps'
He urged any drivers who may have also been targeted, or who may have seen suspicious activity, to contact police.
The targeted lorry was parked so the fuel tank was facing away from the carriageway when the theft happened between 2300 and 2320 GMT.
Adding that lorry drivers were required by law to take rest breaks, he urged them to be vigilant and use lockable fuel caps and anti-siphon devices.
Police were given descriptions of two suspects who were white and in their 30s. One had long hair and one wore a striped tracksuit.