The bill allows doctors to prescribe medicine to adults, who have six months or less to live.
It's an option chosen by a Chicago-area man last year.
Drew Flack is from the area but moved to California, where he learned of his terminal illness.
California is one of 10 states where medically assisted death is already legal.
"I lost both of my parents to terminal cancers, and can't forget the helpless feeling of being unable to relieve their suffering," said state Sen. Linda Holmes, D-Aurora. "This measure is about allowing qualified, terminally ill patients an option to consider ending their pain and distress."
Illinois' Right to Life group calls the bill "horrible," and says it plans to still work to defeat it.