US consumer prices fell 0.3% in November, much more than forecast, even as declining oil prices were expected to cause a contraction, Labor Department figures showed today.
The prices of food and services were higher, but the 3.8% fall in energy prices from October more than offset those rises.
US economists had expected a fall of just 0.1% in the overall consumer price index.
Stripping out volatile US food and energy prices, the core CPI rose 0.1% in the month, in line with forecasts. Year-on-year, inflation was just 1.3%, compared with 1.7% in October.
Factoring out food and energy costs, annual inflation was 1.7%. Food prices gained 0.2% in the month, shelter and transportation services both rose 0.3%, and medical care services increased 0.4%.
The slowdown in inflation eases pressure on the US Federal Reserve to raise interest rates from the zero-level where they have sat for six years.
The Fed completes a two-day policy meeting later today in which it is expected to update the outlook for tightening monetary policy in the coming year.