The court said that the ruling to overturn the controversial aspect of its law on fertility treatment, law 40, was effective immediately.
Lawyer Maria Paolo Costantini, who has campaigned against law 40, said that parliament would re-introduce the rules that existed before the law was implemented, so donor-assisted conception could begin straight away.
But health minister Beatrice Lorenzin said that the issue would need to be debated in parliament before it could be implemented.
'It requires wider approval in parliament', she said, saying that there were still issues around donor anonymity and the potential children's right to know the identity of their genetic parents.
Italy's law 40 places strict restrictions on those seeking IVF and artificial insemination, and fertility treatment is denied to same-sex couples and single people.
Another aspect of law 40, which states that embryos cannot be screened for genetic disorders before they are implanted, will be discussed by the court on June 18. In 2012, the European Court of Human Rights ruled that this contravened the European Convention of Human Rights because it breached the right to respect for family and private life.
An Italian association that promotes the freedom of scientific research, the Associazione Luca Coscioni, said that thousands of couples were considering a class-action lawsuit against the State over damage they have suffered under law 40, according to the Gazzetta del Sud.
'The ruling of the Court is retroactive and states that the ban on third-party donors in assisted-fertility treatments has been illegitimate since the law was approved', said Gianni Baldini, one of the association's lawyers.
'A conservative estimate is that 4,000 sterile couples went abroad in 2012 for a donor and in Spain 62 percent of couples seeking the procedure are Italian', said Costantini.
'Finally, couples won't be forced to travel abroad', oncologist Dr Umberto Veronesi, a former health minister, told Il Messaggero, the Gazzetta del Sud reports. He added that the rule had 'denied a couple's will and desire to become parents of a child they would raise with love'.