Seventy-two per cent of Swiss have voted in favour of legalising abortion, bringing laws into line with most of Europe.
The result means abortion will now be permitted within the first 12 weeks of pregnancy, harmonising the legislation with current practice, which effectively allows abortion on demand.
Until now Switzerland has had some of the most restrictive abortion laws in Europe - despite loopholes in the law - along with the Irish Republic, Poland and Portugal.
Sunday's vote means the Swiss have finally caught up with countries like France and Italy, which introduced liberal abortion laws in the 1970s. Germany and Austria also allow the practice, although counselling is mandatory before a woman can have a termination.
A counter-proposal to tighten Switzerland's 1942 law, which banned the practice unless a women's health was at risk, was thrown out by 82 per cent of voters. That initiative - "For Mother and Child" - would have prohibited abortion even in cases of rape.
The turnout was just over 40 per cent.
In reality, Sunday's vote will lead to little change in most of country, except to simplify the process of securing an abortion.
Loopholes in the existing law, which prohibits terminations unless a woman's health is in danger, have long enabled women to have abortions - currently between 12,000 and 13,000 terminations take place every year. That accounts for about one in every eight pregnancies.
Until now, regional health authorities have been free to decide how to interpret the law. Any licensed doctor can carry out, or approve, an abortion if he or she believes that a pregnancy would put a women's health - including mental health - in danger.
No woman has been convicted for an abortion-related offence since 1988, and only five physicians have been convicted for ignoring the abortion laws in the past nine years.
Sea change in Catholic attitudes
Analysts say Sunday's vote points to a sea change in attitudes among Switzerland's Catholics.
On Sunday, most of the country's Catholic cantons voted in favour of legalising abortion, with only Valais in the south and the tiny central canton of Appenzell Inner Rhodes voting against. In previous votes, Catholic cantons rejected any loosening of the law.
For some cantons - such as predominately Catholic Nidwalden - the vote means they will now have start offering abortions in their own hospitals, rather than sending pregnant women to neighbouring cantons for abortions.
As well as having government backing, the proposal to legalise abortion was supported by parliament and two of the four main political parties. The Protestant Church and the country's main women's organisation, Alliance F, were also behind the proposal.
Opponents of abortion are dissatisfied with the present legislation, but for a different reason. The country's main pro-life group, Swiss Aid for Mother and Child, wants to see an outright ban on abortion introduced, even where the pregnancy is the result of rape.
But the group had the open backing of only one fundamentalist religious party. The main women's organisation and the Protestant Church both came out against the initiative, while the Roman Catholic Church recommended that voters reject both proposals.
Sunday's ballot was the fourth vote on abortion in Switzerland since 1977. All previous attempts to either tighten or ease regulations on a nationwide level have failed to win a majority.
Switzerland's abortion rate is among the lowest of any developed country. Nearly half of all abortions are carried out on women over the age of 30, while teenage pregnancies account for about ten per cent of terminations.