Agüero, who previously played for Manchester City and Atlético Madrid, came to Barcelona for this season.
During a league match against Alaves in October, Agüero suffered from arrhythmia, heart rhythm disorders.
The Argentine complained of chest pain and dizziness during the match and was later taken to hospital.
It was stated that it was about arrhythmia.
After the match, Barcelona announced that the 33-year-old would be gone for three months to examine the heart problems.
Information in the media has later indicated that the striker may be forced to end his career.
On Wednesday, he told a press conference about his decision.
- I have made the decision for the sake of my health.
That's what the doctors told me, that it would be best if I stopped playing.
I made the decision about ten days ago, says Agüero.
- I am proud of my career, it was a dream come true.
I just wanted to be a pro, but I never thought I would play in Europe.
The Argentine is leaving an 18-year senior career where he scored more than 400 goals.
There were 101 A-international matches for Argentina.