About 2,000 people joined a march in Glasgow to show their opposition to the Trident nuclear deterrent and its planned replacement, police said.
Protesters marched through Glasgow city centre
The Bin the Bomb event ended with a rally in George Square.
Senior church figures, politicians and union leaders were addressing marchers. A similar protest was also taking place in London.
The government has said it would be unwise and dangerous for the UK to give up its nuclear weapons.
Reverend Alan McDonald, moderator of the general assembly of the Church of Scotland, said that for the past 25 years the assembly had argued that nuclear weapons were morally and theologically wrong.
Cardinal Keith O'Brien, the Roman Catholic Archbishop of St Andrews and Edinburgh, said his church was speaking out because Trident was "immoral".
He said: "Over a year ago we said Make Poverty History. Now we are saying Make Trident History. Make nuclear war history. That is what is uniting so many people today."
SNP leader Alex Salmond said: "The people of Scotland have shown their opposition to Trident time and again.
"Instead of wasting billions on a weapons system that cannot protect us from terrorism, people would rather see that money spent on schools, hospitals and fighting crime."
Chris Ballance, the Scottish Green Party speaker on nuclear issues, said: "The majority of people in Scotland oppose nuclear weapons.
"When Westminster votes on the issue, Labour MPs should remember that they represent the Scottish people and are not elected to simply nod through Tony Blair's policies."
Another speaker, Scottish Trades Union Congress president Katrina Purcell, said: "The STUC is opposed to all nuclear weapons and believes the most logical way of avoiding conflict is by getting rid of nuclear weapons, rather than escalating the arms race."
In December, Prime Minister Tony Blair outlined plans to spend up to £20bn on a new generation of submarines for Trident missiles, which are currently based at Faslane on the Clyde.
A total of 45 people were arrested when Greenpeace held a protest at the naval base on Friday.
Campaigners used a boat to blockade the base for several hours before the vessel was seized by Ministry of Defence police.