The stampede happened during a play-off match between two popular teams, V Club and TP Mazembe, in the capital Kinshasa. At least 21 other people were injured.
UN-backed Radio Okapi said police had fired tear gas after angry fans threw objects on to the field in the final minutes of the match.
Altercations have previously erupted when V Club have played TP Mazembe.
Sanctions had been imposed last season on the teams after a match between them in the city of Lubumbashi.
More than 20 people were killed on April 25 in the town of Kikwit when generators failed during a festival honouring a popular singer. The stadium was plunged into darkness and caused fans to stampede, resulting in the deaths.