One helicopter's rotor blade appeared to clip the tail of the other chopper, causing them both to crash into the ground, a video posted to social media showed.
The crash happened at a naval base in Lumut, a town in Malaysia's west.
All ten people aboard the helicopters were pronounced dead at the scene, Malaysia's Fire and Rescue Department said.
The victims of the crash have all been identified as members of Malaysia's naval forces.
The two helicopters were undergoing a training exercise when the accident took place.
Malaysia's fire brigade worked to clear the victims from the debris.
Images of one of the crash sites shared by the fire department showed emergency responders working in the wreckage of one of the helicopters.
The scene had been sprayed with white foam.
The fire department said it was notified of the incident at around 9.50am today.
