Zimbabwe's annual inflation rate rose to 502.4% in November, the government's own statistical office has reported.
Finding enough food is now a real issue for many Zimbabweans
An increase on September's 411% level, the rise has been caused by a surge in purchases of bicycles and home rentals.
Bike sales have risen due to a chronic shortage of fuel, and people are seeking new homes after the government's slum clearance programme.
The UN says this affected 700,000 people, although Robert Mugabe's regime says the true figure is much less.
The government said it was simply carrying out the clearances to reduce crime and overcrowding.
Zimbabwe's economy has now been in sharp decline for six years, with severe fuel and food shortages.
While the UN says this is down to mismanagement by the government, Mr Mugabe instead puts the blame on sanctions bought in by Western nations following his controversial seizure of white-owned farms.
The latest rise in inflation comes despite the government's pledge to get the level at or below 300% by the end of 2005.
UN humanitarian chief Jan Egeland said earlier this week that Zimbabwe was in "meltdown", following a visit to the country.