Eurostat, the European Union's statistics agency, said consumer prices were up 1.6 per cent in the year to December, down from the previous month's 1.9 per cent and the lowest since April. Analysts had expected a decline to 1.8 per cent.
Lower energy prices were behind the decline. Over the year, they rose 5.5 per cent against the 9.1 per cent recorded in November.
Stripping out potentially volatile items such as energy, core inflation was steady at 1 per cent.
The fall in the headline inflation rate will likely rein in expectations that the European Central Bank will raise interest rates soon. The ECB aims for an inflation rate of just below 2 per cent.