Greece's annual headline consumer price index turned negative in January at -0.2 percent year-on-year, from 0.7 percent in the previous month, statistics service ELSTAT data showed on Thursday.
The data also showed the EU-harmonized inflation rate slowed to 0.2 percent last month from 1.0 percent in December.
Greece had been in a protracted deflation mode since March 2013 based on its headline index, as wage and pension cuts and a multi-year recession took a heavy toll on Greek household incomes.
Deflation in the country hit its highest level in November 2013 when consumer prices registered a 2.9 percent year-on-year decline. The economy emerged from deflation in June 2016.