Some 2,000 members of a women's peace group marched from the Lincoln Memorial to the Pentagon yesterday where they blocked entrances and shouted their disapproval of what they called the country's "nuclear madness."

About 65 demonstrators were arrested during the protest -- three for smearing what they said was a woman's blood on the River Entrance to the Pentagon, and the rest for blocking entrances, according to Lt. Elliott Grollman of the Federal Protective Service.

Demonstrators who live in the area or were carrying some identification were released after receiving a citation at the Pentagon, he said, while a few others were arraigned before a U.S. magistrate in Alexandria.

Chanting, "Take the toys away from the boys," the protesters encircled the massive, boxlike national defense headquarters, flashing peace signs at Pentagon employes who watched them from the windows. Some of the employes smiled and gave a peace sign back.

Outside the River Entrance, site of numerous previous antiwar demonstrations, groups of women sat down and linked arms and hands so that employes had to step over them to pass through.

"Shame, shame, shame" and "What about the children?," they shouted, waving clenched fists at the uniformed servicemen who went in or out of the building.

The demonstrators came from as far as Vermont, Massachusetts and Kentucky to march in the bright, Indian summer-like day. Last year, many of the same women staged a similar demonstration at the Pentagon and more than 100 were arrested.

Though nuclear proliferation was the main target of the protest, the women said they were also demonstrating against the Reagan administration's cuts in social services and U.S. involvement in El Salvador, as well as for women's equality and gay rights.

"Women are angry about the antiabortion measures in Congress, the cuts in Title IX, the cuts in day care," said Lynn Anderson, 27, who rented a van with a group of 17 others to drive from Louisville, Ky., to attend the march. The Pentagon was the "focus of anger," she said, because it is a "blatant symbol of male dominance."

When the Women's Pentagon Action came to Washington last year, they said they wanted to "send a message" to the new administration to stop the buildup of nuclear arms. Yesterday, one of the leaders of the group said that the message had gone unheeded.

"It took seven years for the Vietnam War protests to take effect," she said. "And we'll be back next year -- if there is a next year."