A federal appeals court on Friday upheld former Giants slugger Barry Bonds' obstruction-of-justice conviction stemming from rambling testimony he gave during a 2003 appearance before a grand jury investigating elite athletes' use of performance-enhancing drugs.

The 9th U.S. Circuit Court of Appeals ruled that Bonds' testimony was ''evasive'' and capable of misleading investigators and hindering their probe into a performance-enhancing-drug ring centered at the Bay Area Laboratory Co-Operative, better known as BALCO.

In a statement Friday night, Bonds said he was disappointed but he has instructed his attorneys to ask that he be allowed to immediately begin serving his sentence of 30 days of house arrest and two years of probation.

''Meanwhile, I also intend to seek further judicial review of the important legal issues presented by the appeal that was decided today,'' Bonds said. ''This has been a long and difficult chapter in my life and I look forward to moving beyond it once I have fulfilled the penalties ordered by the court.''

Like several other prominent athletes who testified before the grand jury, Bonds was granted immunity from criminal prosecution as long as he testified truthfully.

But after Bonds repeatedly denied knowingly using performance-enhancing drugs - he testified he thought he was taking flax seed oil and other legal supplements - prosecutors charged him with obstruction and with making false statements.

A jury convicted Bonds of a single felony count of obstruction, stemming from when he was called before the grand jury in San Francisco in December 2003. Bonds was asked whether his trainer, Greg Anderson, had ever injected him with a substance, and he replied by discussing the difficulties of being the son of a famous father. Bonds' father is former major leaguer Bobby Bonds.