Every Year 8 schoolgirl in Wales is to be offered a vaccination against the virus which causes most types of cervical cancer, from this month.
Some 20,000 secondary school girls aged 12 and 13 will be offered the vaccine against the human papillomavirus(HPV).
The jab protects against two viruses responsible for about 70% of cases. Wales has around 170 cases a year.
However, some experts have said another vaccine, the most used worldwide, would have been a better option.
Youngsters in Powys, Bridgend and Swansea are expected to be the first to be offered the jab, at the end of September.
A two-year catch-up vaccination scheme from autumn 2009 aims to target another 40,000 girls up the age of 18.
The scheme is part of a UK wide programme to tackle cervical cancer, the second most common cancer in women under 35.
In Scotland, the vaccination programme in schools began this week.
The scheme uses Cervarix, manufactured by GlaxoSmithKline. The vaccine was picked after a competitive tendering process ahead of the other contender, Gardasil.
However, when the UK's Department of Health awarded the contract, some health bodies criticised the decision.
The Terrence Higgins Trust called it "short-sighted" and said it would be a false economy, while the Family Planning Association said the alternative "would've been a huge preventative measure in terms of health and financial costs to the NHS".
The UK Government insisted Cervarix came out on top after rigorous assessment.
The vaccine protects against two strains of HPV but will not completely wipe out cervical cancer because it does not protect against every type of high-risk HPV.
Julia Frater, senior cancer information nurse at Cancer Research UK, described the programme as "an exciting step in the fight against the disease".
She said: "Our message is to take up the opportunity to get vaccinated but it's equally important to go for screening when you're invited.
"Screening can prevent cervical cancer by detecting unusual changes in the cervix before cancer develops and it saves around 5,000 lives in the UK each year.
The Welsh Assembly Government is meeting the cost of the vaccination programme.
Health Minister Edwina Hart said: "Prevention is always better than cure and this vaccine will prevent many women from catching the human papillomavirus in the first place.
"Tackling cancer is one of our One Wales priorities and the routine immunisation of girls is a long-term investment in cervical cancer prevention."
Women in Wales aged 20 and 64 are given routine cervical cancer screening (smear tests) every three years.