Barry Bonds has been charged on five counts

Prosecutors allege that Barry Bonds lied under oath when he said in 2003 that he had never knowingly used performance-enhancing drugs.

He denies accusations that he used a previously untraceable steroid from a San Francisco company called Balco.

In September he became the sport's record home run hitter, with 755.

Making it into the record books as the man who had hit more home runs than anyone else in baseball history should have been the crowning achievement of Mr Bonds' storied career, says the BBC's David Willis in San Francisco.

Drugs probe

Yet, by then, the rumours were rife that the San Francisco Giants player's success owed less to raw talent and hard training and more to performance enhancing drugs.

An investigation into Balco's activities has already led to the downfall of several other top athletes, among them the Olympic sprinter Marion Jones.

She recently relinquished the five medals she won at the Sydney Games after admitting using steroids.

Mr Bonds has been charged with four counts of perjury and one count of obstruction of justice over an inquiry into drugs use.

The 43-year-old appeared at a district court in San Francisco on Friday, where he pleaded not guilty to the charges.

He continues to deny knowingly taking performance enhancing drugs.