The two Italians were among a group of eight climbers caught up in the avalanche at about 4.00am (02.00 GMT) as they were ascending Mont Blanc du Tacul at an altitude of 4,200 metres, the gendarmerie in the Haute-Savoie region said.
The mountain is in the same range as Mont Blanc, the highest peak in western Europe, which attracts thousands of climbing enthusiasts every year.
Set off by blocks of falling ice, the avalanche carried the party for about 400 metres.
Rescuers later found the two women, aged 37 and 41 and both from Italy's Piedmont region, dead under the snow.
An Italian mountain guide was rescued alive but was suffering from severe hypothermia and was in intensive care in a hospital in nearby Annecy.
Others in the party – including a Greek mountain guide and a climber, and three other Italian climbers – escaped unharmed and returned to a refuge.
Rescuers spent several hours searching for another climber who it was thought may have been caught up in the avalanche, but gave up because it was unclear whether the person had been in the area.
Officials said about 30 climbers had been making the ascent at the time of the avalanche.
Meanwhile the bodies of two French climbers were found Tuesday morning at the bottom of a 20-metre crevasse on Roche de la Muzelle, a mountain in the Ecrins massif of the Alps.
Mountain rescue services in the Isere region said the couple had left a refuge on Monday morning and appeared to have fallen into the crevasse on their descent from the summit.
Officials said the woman was 51 and the man about 60, and that both were from southeastern France.
Laurent Soullier of the Grenoble mountain rescue service said there was no link between the two incidents and added that the number of accidents in the Alps rises in the summer as visitors flow in to the area.
"Regarding the accident in Mont Blanc, falling blocks of ice (which caused the avalanche) are a well-known phenomenon in this area," Soullier said.
"If people are making this crossing, it is because they are accepting the risk….short of completely cutting off access, I don't see how we could avoid this kind of tragedy."
Thousands of tourists flock to the French Alps annually for sports including mountain climbing and skiing, but every year some fall victim to accidents.
Each summer, some 20,000 climbers attempt to reach the summit of Mont Blanc, with up to 500 a day during peak times.
In the deadliest accident in years, nine Europeans – three Germans, a Swiss, two Spaniards and three Britons – were killed in July last year after an avalanche engulfed a group of climbers in the Mont Blanc massif.