It seems his wife, Molly McNearney, has been the recipient of several cruel messages as well.
On Monday, McNearney, co-head writer for "Jimmy Kimmel Live!" hit back at "trolls" who have said mean things to her in the wake of recent news.
"My baby has a hole in his heart. My dad lives in Puerto Rico. If you think a nasty tweet will shake me, you are mistaken," she wrote. "Beat it, trolls."
Last week, Kimmel, 49, slammed Republican Sen. Bill Cassidy for co-sponsoring a new health care bill that, according to the late night host, failed the "Jimmy Kimmel Test" he proposed in May. At the time, Cassidy said that any health care legislation would provide adequate coverage to those with pre-existing conditions -- like Kimmel's son, Billy, who was born with a heart defect that required immediate surgery -- with no lifetime caps.
"A lot of people have been saying that I'm not qualified to talk about this," Kimmel said last week. "And that is true, I'm not qualified to talk about this, but I think those people forget -- Bill Cassidy named this test after me. Am I supposed to just be quiet about that?"
"We are the lucky ones. You shouldn't have to be 'lucky' to be cared for in this country. We're fighting for others. You should too," McNearney added on Twitter. "It would be irresponsible knowing what we know and experiencing what we experienced to 'stay in our lane.' Move over. We're merging."