The Cessna 208 aircraft smashed into the hanger at a sky diving centre during bad weather on Monday, authorities said, The Evening Standard reported.
The plane’s pilot and four people sheltering in the hangar from stormy weather died in the afternoon crash in Chrcynno, firefighters spokesperson Monika Nowakowska-Brynda said.
Eight people were injured, two of them seriously, police said. A child was among the injured, the provincial governor, Sylwester Dabrowski, said.
Chrcynno is about 28 miles north-west of Warsaw.
Firefighters and airborne ambulances took the injured to hospitals in the Nowy Dwor Mazowiecki area.
Prosecutors and police are investigating the cause of the accident.
It is the worst accident related to sky diving in Poland since 2014, when 11 people were killed in a crash of a small plane in Topolow, near the southern city of Czestochowa.