The Syrian Observatory for Human Rights said the deaths brought the total number of IS fighters killed in the ground battle for Kobane to 576 since clashes there began on September 16.
"Over the last three days, at least 100 members of the Islamic State and its religious police have been killed... In Kobane and its surroundings," the Britain-based group said.
It said the IS members had come from Aleppo and Raqa provinces to take part in the battle for the town, which is being defended by members of the Kurdish People's Protection Units, or YPG.
Overall, 958 people have been killed in the battle for Kobane -- 576 Is jihadists, 361 YPG fighters and allied forces and 21 civilians, according to the Observatory.
More than 180,000 people have been killed in Syria's conflict since it began in March 2011, says the Observatory, which relies on a network of sources on inside Syria for its reports.