17 soldiers, including four officers, and more than 100 militants were killed.
Some reports, citing local officials, put the army death toll higher.
Near simultaneous raids were launched on at least five military check points and a police station around Sheikh Zuweid on Wednesday.
The attack was one of the largest co-ordinated assaults by IS militants in Sinai.
Eye-witnesses reported seeing militants roaming the streets of the northern town on Wednesday, clashing with armed forces.
