The Labour leader told activists during a speech in Bedford: "Every single person in our country could make the difference in this election."
He warned that the NHS faced "savage cuts" and a "financial time bomb".
He promised to "keep going to the last minutes of the last hours of this campaign to rescue the NHS."
The best of BBC News' Election 2015 specials
Ed Miliband has made a plea for people to come out and vote on 7 May, claiming the race to govern "is going to be one of the closest we've ever seen".