[1] Barros started racing motorcycles at the age of 8, when he won on his debut in the Brazilian minibike championship.

In 1990, Alex Barros was the youngest rider in history to join the top motorcycling category, the 500cc, at the age of 20.

Notable results included 8th in the United States and Germany, and 5th in the Belgium Grand Prix.

After qualifying third in the US Grand Prix, Barros had his first victory in Spain, finishing that year's world championship in sixth place.

2003 was a difficult one for Barros due to injuries, but in 2004, he once again finished the championship in fourth, in a season dominated by Valentino Rossi, Sete Gibernau and Max Biaggi.

In 2005, Barros returned to the top of the podium in Portugal,[4] however he did not mount a lasting championship challenge, and was not offered a ride for 2006.

For 2006 he was hired by the Klaffi Honda team in the Superbike World Championship (WSBK), paying around £100,000 of his own money to fund the ride.

At Brands Hatch he failed to qualify for Superpole, but bounced back from 18th on the grid to take a pair of top 10 finishes.

In 1999, Barros and Japanese teammate Tadayuki Okada won the Suzuka 8 Hours endurance race riding a Honda RC45 superbike.