The incident occurred around 11.35am in the Marchairuz pass in the canton of Vaud, cantonal police said.
The motorcyclist was passing a bicyclist travelling in the same direction when he colllided with the van, which was heading in the opposite direction, police said.
From the shock of the impact, the victim was thrown from the motorbike to the ground.
A doctor and ambulance attendants arrived at the scene before a Rega emergency rescue helicopter transported the man in critical condition to the university hospital in Lausanne (CHUV), police said.
The senior, who resided in the western part of Vaud, died at the hospital in the middle of the afternoon.
Specialists from the traffic division of the Vaud gendarmerie, who were among the officials responding to the scene, are conducting an investigation into the accident, police said.
At an elevation of 1,447 metres, the Marchairuz pass connects the towns of La Brassus in the Vallée du Jeux and Bière.