The reading was 0.1 percentage point lower than an earlier estimate of 5.5 percent by the labour ministry.
There were around 846,600 people without jobs across the nation at the end of February, up from 837,600 a month earlier, according to the state-run Statistics Poland (GUS) agency.
The statistics office reported last week that employment in Polish companies dropped by 0.9 percent in February on average in year-on-year terms.
According to the European Union's Eurostat statistics agency, which uses a different methodology, unemployment in Poland stood at 2.6 percent in January, marking the lowest rate in the 27-nation bloc.
(gs)
Source: IAR, PAP