It is organized by the Union of Russian Ice-cream Produces, the Moscow Ice-cream Association and the Moscow government.
The festival is a charity event and is financed by ice-cream producers. It is dedicated to veterans of the Great Patriotic War (1941-1945) and children from underprivileged families.
According to Valery Yelkhov, the executive director of the Union of Russian Ice-cream Produces, veterans get ice-cream free of charge.
About 25 tons of ice-cream are to be sold today, he said.
Some 100 additional ice-cream shops were opened in the Sokolniki park.
"Ice-cream prices at the festival are 20% lower than in Moscow," Yelkhov told RIA Novosti.
About 150,000-250,000 Muscovites and guests of the capital attend the festival every year.
Irina Ivantsova, a housewife, who came to Sokolniki with her son said: "Such festivals are a remarkable tradition. Both children and adults like them very much."