The Argentine genius is the club's all-time top scorer and appearance maker, with 672 goals in 778 games in all competitions.
Despite almost departing last summer, Messi had agreed to a 50 per cent pay cut, and wanted to remain with the Spanish giants.
But Barca president Joan Laporta said on Friday he was not prepared "to put the club at risk" by renewing Messi's contract, as the club face up to huge financial problems ahead of the start of La Liga on August 15.
“The best player in the world has other offers,” said Laporta, “and he deserves to have everything. He has shown his love for Barcelona and his desire to stay. I am very sad but also convinced I have done the best for Barca.”
Paris Saint-Germain, who bought Neymar from Barcelona for a world-record $264 million in 2017, appear favourites to sign Messi, according to reports in France.
Messi has won 34 trophies in 17 seasons with Barcelona. He helped the club win the Champions League four times, La Liga 10 times, the Copa del Rey seven times and the Spanish Super Cup eight times.
All his stats, goals, and silverware can be seen season by season in the picture gallery above. To view the next image, click on the arrows or swipe if on a mobile device.