The match against Hibernian in the Scottish Premier League had to be abandoned after a supporter suffered a heart attack in the stand just five minutes into the second half
It is believed the supporter, who was in his 50s, suffered a heart attack in the East Stand of Rugby Park just minutes after the second half restarted.
Referee Kevin Clancy called the players off the pitch at the earliest opportunity, with an ambulance taking the supporter to hospital, but a spokesman for Police Scotland confirmed he later passed away.
Kilmarnock manager Kenny Shiels told reporters: "Obviously it was quite serious so Pat Fenlon and I both agreed that the game should be abandoned.
The father of Liam Kelly suffered a heart attack during Kilmarnock’s league cup celebrations in March 2012, and just one month later an Inverness fan collapsed and died during a game against Kilmarnock.
"We need to show respect to the relevant families. Football is not as important as human life so we have shown our respect," Shiels added.