Kirk checked himself into a hospital in the Chicago suburb Lake Forest on Saturday where doctors discovered an "carotid artery dissection."
Kirk was transferred to Northwestern Memorial Hospital on Sunday where further tests revealed that he had suffered an ischemic stroke.
"Due to his young age, good health and the nature of the stroke, doctors are very confident in the Senator's recovery over the weeks ahead," the statement said.
Kirk, a native of Champaign, Illinois, was elected to the House of Representatives in 2000 and to the Senate in 2010.
