Ferrari said the German, who flew to Barcelona from Rome on Monday after he and teammates had presented Pope John Paul with a model F2004 car in an audience at the Vatican, lapped the Circuit de Catalunya in one minute 14.834 seconds.
Schumacher's time compared well with the testing benchmark of 1:13.797 set by BAR's Takuma Sato last year.
However the German, testing for the first time since the season ended in Brazil in October, was driving last year's car without the 2005 modifications designed to reduce speeds.
"They chose to go back to the 2004 configuration because the track was so slippery this morning," said his spokeswoman Sabine Kehm. "But it was a good day for Michael."
Schumacher agreed it was good to be back.
"In the evening I drove down to the track and had dinner with the lads," he said on his website. "After all, I hadn't seen the test team for a while.
"It felt good to be at the track again and I really enjoyed that feeling this morning as well."
Schumacher, winner of 13 races last season, had to wait until late in the morning to get up to speed due to cold and damp conditions at the recently-resurfaced circuit.
Rivals BAR, worried that they would be unable to get any meaningful data from the track in its current state, have already switched a planned test of their new car to the Valencia circuit to the south.
To try and improve conditions, the Barcelona authorities ran a road car around the circuit day and night on Monday to give the surface more grip.
Barcelona will host the Spanish Grand Prix in May, a race that should also be the competitive debut for Ferrari's 2005 challenger.
Ferrari have won the last six constructors' titles.
