The motion brought by the conservative Federal Democratic Union party sought to impose a one-year residence requirement in the Zurich canton for those who resort to legally sanctioned assisted suicide.
A locally based association, Dignitas, has gained notoriety over the past decade by offering more than 1,000 foreigners, mainly terminally ill people, the opportunity to take advantage of relatively permissive Swiss laws.
The motion was rejected by 218,602 votes to 60,186 or 78.4 percent. A second motion calling for a national ban on assisted suicide was also rejected by 234,956 votes against 43,165 or 84.5 percent.
"The right to die is a private matter that does not concern the state and the Church even less so," vice president of the assisted suicide association Exit, Bernhard Sutter, told AFP.
"It's a clear sign from Zurich and corresponds with Switzerland's humanitarian tradition of coming to the aid of others," he said.
In Switzerland a person may be given "passive" assistance to suicide, such as being supplied with a lethal dose of a drug, provided it is not done for selfish motives or for gain.
Active assistance, including helping the person to take the drug or administering it, is forbidden.
Dignitas, a Swiss organisation founded by controversial human rights activist Ludwig Minelli that assists the terminally ill, said that by the end of 2010 it had worked with 1,138 people seeking to end their lives.
The list includes 592 people from Germany, 102 from France, 118 Swiss nationals, 19 Italians, 18 US nationals and 16 people from Spain.
The group says that in the last decade it has approached more than 1,000 foreigners about benefiting from Swiss assisted suicide laws.