A vehicular power unit mount structure having a first mounting member for attachment to a power unit and a second mounting member elastically connected to the first mounting member for attachment to a vehicle body. The mount structure includes an elastic waterproofing cover having an axial displacement stopper and a radial displacement stopper. The axial displacement stopper is engageable with an end of a tubular portion of the second mounting member to elastically absorb impact shock and eventually stop movement of a shaft portion of the first mounting member when the shaft portion is displaced in an axial direction toward the second mounting member. The radial displacement stopper is engageable with an inner cylindrical surface of the tubular portion to elastically absorb impact shock and eventually stop movement of the shaft portion when the shaft portion is displaced in a radial direction relative to the second mounting member.