Bjorn fired a 9-under-par 63 at the Golfclub Munchen Nord-Eichenried to take the 36-hole lead at the BMW International Open.
At 12-under-par, Bjorn leads Miguel Angel Martin and Padraig Harrington by one shot entering the weekend. The Dane carded nine birdies and no bogeys on Friday to overtake first-round leaders Per-Ulrik Johansson, who shot 74 and fell into a tie for 29th, and David Gilford, who dropped into a tie for 17th after shooting 73.
Despite being winless, Bjorn has had major success in 2000. He played with Tiger Woods in the final group on Saturday at the U.S. Open. He tied for 2nd at the British Open and finished 3rd at the PGA Championship.
A four-time European Tour victor, Bjorn is seeking his first triumph since the 1999 Sarazen World Open.
Unlike his fellow 1999 Ryder Cup Team member, Harrington has posted a victory this season. The Irishman captured the Brazil Sao Paulo 500 Years Open in April.
Harrington followed up a first round 67 with a Friday 66 to move to 11-under-par for the tournament. Second place is a familiar position for Harrington at the BMW. That's where he finished after 72 holes a year ago.
'I've no idea why I tend to do well here,' said Harrington, who also led the BMW after two rounds in 1997. 'I just like the event. BMW looks after us very well and I feel comfortable playing here. I am not really thinking about winning. It's one shot at a time. Anyway, Thomas Bjorn is playing very well so it will take a lot to beat him.'
Greg Norman is five shots off the lead after rounds of 67-70. Ernie Els is nine back at 3-under. Defending champion Colin Montgomerie never recovered from the two-shot penalty he incurred due to a late arrival for his Thursday tee time. Monty posted rounds of 72-74 to miss the cut. It's the Scot's first missed cut worldwide since he did so at this very tournament two years ago.