People's understanding of chlamydia has increased dramatically in the past few years, official figures show.
People with chlamydia may not have any symptoms
The Office for National Statistics survey of 3,000 people found 91% of women and 79% of men know chlamydia was a sexually transmitted infection.
Five years ago, just 65% of women and 35% of men knew about the disease.
The Omnibus survey also showed 5% of women had used emergency contraception in the past year, and that the Pill was the most commonly used contraceptive.
The ONS found a fifth of women had been tested for chlamydia at some point in their lives, and 27% had been tested in the past year.
The data, collected in 2005/06 showed women aged 16-29 were most likely to have had a test for chlamydia than older women.
Women who had had more than one sexual partner in the past year were also more likely to have had a test than those with one partner.
Among respondents who knew chlamydia was an STI, women were twice as likely as men to give correct responses to questions about symptoms.
The National Chlamydia Screening Programme was launched in England in 2003 and has screened around 18,000 young men and women in it's first year, and 60,698 in its second year.
The Department of Health plans to have a national screening programme for under 25s by 2007.
The ONS survey also asked about contraceptive use and sexual behaviour.
Of the 5% of women who had used emergency contraception in the past year, 45% had obtained it directly from a chemist or pharmacy, 30% from their own GP or practice nurse and 24% from a family planning clinic.
Overall, three-quarters of women under 50 years were using contraception and the pill was the popular method, closely followed by the male condom.
The vast majority of women who used a condom said the reason was to prevent pregnancy, with 43% saying they used condoms to prevent infection.
Most men and women had only had one partner in the past year, the survey found.
A total of 12% of men and 7% of women said they'd had sex with more than one person in the past year.
Over half of men and women said they made no changes to their behaviour as a result of what they had heard about sexually transmitted infections.
But 37% said they had increased their use of condoms, 9% had fewer one night stands and 3% had a test for STIs.
Lisa Power, Head of Policy at Terrence Higgins Trust said: "We're very pleased the message about chlamydia is getting through. This shows that health promotion campaigns can work.
"However the UK still has the highest teenage pregnancy rate in Western Europe and sexually transmitted infection rates overall continue to rise.
"Young people must be taught the skills they need to protect themselves, not just from unwanted pregnancy, but also from sexually transmitted infections (STIs) and HIV."
Dr Richard Ma, a GP in Islington, North London and member of the Royal College of GPs Sex, Drugs and HIV Task Group said the increase in awareness about chlamydia was probably partly because of the screening programme.
But he added: "That has to be balanced with access to treatment and testing services. The demand for STI testing is not matched by provision of services."
A spokesperson for the Department of Health said: "We recognise that young women are more likely to use health services such as GPs and that is why our programme is currently targeting men by introducing screening at venues such as further education colleges, armed forces bases and male prisons, unlike other countries which focus solely on women."