Casillas, who made 725 appearances for Spanish giants Real Madrid, was hospitalised after collapsing with an acute myocardial infarction earlier this month.
Reports suggested the 37-year-old World Cup winner was on the brink of retirement but he took to Twitter on Friday to confirm he is going nowhere.
He wrote: 'There will be a day I have to retire. Let me announce the news when that time comes.
'For now, quiet. Yesterday I had a review with Dr. Filipe Macedo. All very well.
'That's really great news I wanted to share with everyone!'.
Casillas was discharged from hospital five days after his scare but hinted he may have to call time on his career.