Nepal police said the chopper of Kathmandu-based Mountain Helicopters came down in a forested area north of the capital. It was returning to Kathmandu when it crashed at Yamuna Balefi Village in Sindhupalchowk district.
Bodies of three men and a woman were recovered by Nepalese troops from the crash site. Rescuers were trying to take the bodies to Kathmandu, a senior official said.
The chopper had caught fire.
Another helicopter has been dispatched to the crash site.