Last weekend people with links to the neo-nazi "Party of the Swedes" clashed with a feminist demonstration on International Women's Day in Malmö. Four people were hurt, one of them is still in a serious condition in hospital.
A local Stockholm school was also hit by anti-semitic graffiti this week.
Stockholm police say they were ready to deal with "any situation that may arise", but were not expecting any trouble at today's demonstration at Medborgarplatsen, news agency TT reports.
More demonstrations are planned in other cities today and tomorrow, including a large one in Malmö tomorrow.
Meanwhile, Malmö football club MFF has now decided to allow supporters to hold a banner saying "The MMF Family Stands United Against Nazism".
Team supporters wanted to raise the sign at a match today, but the team management first asked the fans not to raise the sign. One of the victims in the attack in Malmö last weekend, currently still in hospital, was an active fan of the club.
Magnus Eriksson, head of the Malmö club's supporter movement, says he could not understand the club's original decision.
"It's a shame", he told news agency TT, "we have had long discussions. It seems like it's ok to be against racism, but not nazism."
The club changed its mind shortly before kick-off, and gave permission for the banner to be unfurled at the match.