Some 85% of the 278,000 votes cast opposed the ban on assisted suicide and 78% opposed outlawing it for foreigners, Zurich authorities said.
About 200 people commit assisted suicide each year in Zurich, including many foreign visitors.
It has been legal in Switzerland since 1941 if performed by a non-physician with no vested interest in the death.
Assistance can be provided only in a passive way, such as by providing drugs. Active assistance – helping a person to take or administer a product – is prohibited.
While opinion polls indicated that most Swiss were in favour of assisted suicide, they had also suggested that many were against what has become known as suicide tourism.
Many citizens from Germany, France and other nations come to die in Switzerland because the practice remains illegal abroad.
One local organisation, Dignitas, says it has helped more than 1,000 foreigners to take their own lives.
Another group, Exit, will only help those who are permanently resident in the country – saying the process takes time, and much counselling for both patients and relatives.
Assistance can be provided only in a passive way, such as by providing drugs
Its vice-president, Bernhard Sutter, said the result showed Swiss voters believed in “self-determination at the end of life”.
The referendum had offered a proposal to limit suicide tourism, by imposing a residency requirement of at least one year in the Zurich area in order to qualify for the service.
The BBC’s Imogen Foulkes, in Geneva, says the size of the vote against a ban on assisted suicide reflects the widely held belief among the Swiss that is their individual right to decide when and how to die.
Their rejection of the proposal to limit assisted suicide to those living in Zurich shows that concerns about suicide tourism carry less weight with voters than their conviction that the right to die is universal, our correspondent says.
But the debate in Switzerland will continue, she adds. Polls show voters do want clearer national legislation setting out conditions under which assisted suicide is permitted.
The Swiss government is planning to revise the country’s federal laws on assisted suicide.
It has said it is looking to make sure it was used only as a last resort by the terminally ill, and to limit suicide tourism.
I think the above picture says it all for me.
I used to know a lady livening in a basement flat, She had lived there since the 1940’s and I would say she was in her late 80’s.She suffered in her last years from bad health but every time I called into see her she would always grasp her front door keys and say as long as I have these (Keys) I have my dignity .I suppose she was saying as long as I am independent, I am responsible for myself and she felt respected .She used to say life is but a train journey ,we are all on this journey and we all see other people getting off at the various stops and sometime soon we will come to my stop .That to me is the essence of the one true religion .She died surrounded by her family and she is so missed every day!
Bottom line .We as independent people should have the right to decide when ,where and how we die .