The "morning-after" contraception pill will now be available without a prescription following the recent relaxation of rules by the Spanish Government.
"It is an emergency method of contraception, not to be used except in emergencies," said Health Minister Trinidad Jimenez. "We don't want it to become another means of contraception."
Within three months, she said, pharmacies will be able to sell the morning-after pill to persons of any age.
The contraceptive, which can be used up to 72 hours after sexual intercourse, has hitherto been available only on prescription.
Other countries which have allowed over-the-counter sales of the pill, including France, Britain and the United States, had seen a "significant" drop in the number of unwanted pregancies, Jimenez told a news conference.
The number of abortions in Spain doubled between 1998 and 2007, according to health ministry figures.
The government plans to ease the country's abortion laws to offer greater legal protection to women who wish to have an abortion and doctors who carry out the procedure.
But the measure has drawn the ire of the Roman Catholic Church and other conservative groups.
Spain decriminalised abortion in 1985 but only for certain cases: up to 12 weeks of pregnancy after a rape; up to 22 weeks in the case of malformation of the foetus; and at any point if the pregnancy represents a threat to the physical or mental health of the woman.