Activists said to Radio Sweden there were 3,000 people there, despite the chilly rain.
The police confirmed this estimate to news agency TT.
Large protests were also held in the other big Swedish cities of Gothenburg and Malmö, all as part of a global day of solidarity with Kobane, including in places such as Istanbul, London and Paris.
The Kurdish fighters of the YPG/YPJ militia have been defending a city for over a month.
Kobane is formally in the borders of northern Syria, but has a Kurdish population.
Around 150 Peshmerga fighters from the neighbouring Kurdish Regional Government, officially in Iraq, arrived on Friday night to strengthen the resistance.
US-led bombing raids are also trying to stop the "Islamic State" take the city and secure an important border crossing into Turkey.
People from Sweden are known to have gone to defend Kurdish areas from the extremist "Islamic State", notorious for its mass killings and for taking many into slavery.