Pilots at Wiltshire Air Ambulance were targeted by a laser pen on Saturday night.
The incident, the latest in a long series of laser pens being shone at aircraft over Wiltshire, happened at around 10.30pm on Saturday evening.
The crew later tweeted: "Once again to the idiots who decided to laser us while on approach to landing back at Devizes, you have no idea how dangerous this is."
The crew had been attending the scene of an accident in Corsham on Saturday evening, and were approaching the helicopter's base in Devizes.
Last month, police had to confiscate a laser pen from a seven-year-old boy from near Calne who managed to distract the pilots of an Airbus jet beginning its approach to land at Bristol Airport.
And a man from Trowbridge was fined by magistrates for shining a laser pen at the air ambulance last year.
