Also called

  • STI, STD, sexually transmitted infection, sexually transmitted disease


  • Chlamydia is a very common sexually transmissible infection.
  • If left untreated, chlamydia can cause pelvic inflammatory disease in women, which can lead to chronic pain and infertility. 
  • In men, untreated chlamydia can cause pain and swelling in one or both testicles.
  • If detected early, chlamydia may be treated with a single dose of antibiotics.
  • Partners of people with chlamydia also need to be informed, tested and treated as they may be infected too. If so, there is a risk they could reinfect the person who has been treated for chlamydia.

Chlamydia is caused by the bacterium Chlamydia trachomatis and is a very common sexually transmissible infection (STI).

It is often called the ‘silent infection’ because most people do not realise they have it.

It can affect women and men of all ages, but most frequently occurs in young people (under 25) who regularly change sexual partners.

Chlamydia is spread by having unprotected sex of any kind with an infected person.

Who is at risk of chlamydia?

Anyone who is sexually active is at risk of chlamydia. You are at increased risk of infection if you:

  • Are young (under 25).
  • Often have different or multiple sexual partners.
  • Have any type of unprotected sex (without condoms) with someone who is infected with chlamydia.

What are the symptoms of chlamydia in women?

Most women with chlamydia, have no signs or symptoms.

It can infect the cervix and spread to the uterus and fallopian tubes, causing:

If a pregnant woman has chlamydia, it can pass on to her baby during childbirth – causing lung or eye infections.

In women (if symptoms are present),  may include:

What are the symptoms of chlamydia in men?

Men who have chlamydia usually do not have any signs or symptoms.

In men, chlamydia infects the urethra and may spread to the epididymis – the tube that carries sperm from the testicles.

In men (if symptoms are present), may include:

  • discharge from the penis
  • discomfort when urinating
  • sore, swollen testes.

How often should I get checked for chlamydia?

Sexual health check-ups are recommended for anyone who is sexually active.  Frequency of testing also depends on your STI risk:

  • An annual sexual health check-up (which includes chlamydia testing) is highly recommended if you are sexually active – especially if you are under 25.
  • Get checked more often during the year if you frequently change sexual partners.
  • Remember, you are at greater risk if you have sex without a condom with 1 or  multiple sexual partners.

How does chlamydia spread?

Chlamydia is spread when a person has unprotected sex (sex without a male or female condom or dental dam) with an infected person.

Because chlamydial infection often has no symptoms, many people do not realise they have the infection.

Even if you know a person well, you may not be able to tell they have an STI, because people can look healthy and still have chlamydia.

Remember, you can get chlamydia and other STIs from a new sexual partner who has in the past had sex with someone who is infected.

It can also be spread from a long-term partner who has had sex with other people.

How is  chlamydia diagnosed?

Chlamydia is an easily diagnosed and curable STI.

Tests are painless and usually involve either:

  • a simple urine test
  • swab from the vagina, cervix, anus or penis.

The specimen is then sent to a laboratory for testing.

Getting your chlamydia test results

Test results are normally available within a week.

How is chlamydia treated?

If detected early, chlamydia can be treated with a single dose of antibiotic.

If complications from chlamydia infection are present – such as pelvic inflammatory disease (PID) in women – a longer course of antibiotics will be required.

Do not have sex for 7 days after you and your current partner have completed treatment. This includes all kinds of sex (vaginal, anal and oral) with or without a condom.

You can get reinfected with chlamydia if you have sex within the 7 days.

After you have completed treatment, have another test for chlamydia in 3 months’ time to make sure you have not been re-infected.

Can you get reinfected with chlamydia?

Chlamydia reinfection is common. Having chlamydia once does not stop you from getting it again.

Even after you’ve been successfully treated, you can still be reinfected if you have  unprotected sex with someone who has the infection.

Letting partners know you have chlamydia

Sexual partners may be infected too. If you have chlamydia, anyone you have had sex with  from the last 6 months needs  to be informed, tested and treated.

If they don’t know, they could reinfect you or infect someone else if they are not treated. don’t receive treatment.

Most people will appreciate being told they may have an infection and it is an important step in preventing further infection in the community.

Your local GP and sexual health centre can help you inform your partners and let them know that they need a test. This process is called ‘partner notification’. It can be done anonymously, and your confidentiality is always respected.

You can also anonymously notify your sexual partners of the need to get tested and treated for chlamydia via the Let Them Know website if you feel unable to speak to them personally.

There are also nurses (called partner notification officers) who can help you anonymously notify your partners. They can be contacted on (03) 9096 3367.

How to help partners get treatment

If you are not sure whether your sexual partner(s) will seek treatment,  ask your doctor for extra chlamydia medication (or a prescription). You can give it to them  so they can be treated as soon as possible.

This is known as patient delivered partner therapy (PDPT) for chlamydia. Talk to your doctor to see if PDPT is right for you and your sexual partner(s).

Reducing chlamydia transmission

Safer sex practices reduce the risk of STI transmission. Ways to reduce your risk of catching chlamydia include:

  • Practise safe sex – use condoms and water-based lubricant (lube) for all types of sex. Female, (or internal) condoms can also be used for vaginal or anal sex.
  • If you are sexually active, get a full sexual health check (including tests for syphilis, HIV, gonorrhoea and chlamydia) at least once a year. Get checked more often if you frequently change sexual partners.
  • After you have completed chlamydia treatment, get tested in 3 months’ time to check you have not been re-infected.

Where to get help


More information

Sexually transmissible infections

The following content is displayed as Tabs. Once you have activated a link navigate to the end of the list to view its associated content. The activated link is defined as Active Tab

Preventing STIs

Content Partner

This page has been produced in consultation with and approved by: Melbourne Sexual Health Centre

Last updated: November 2020

Content on this website is provided for information purposes only. Information about a therapy, service, product or treatment does not in any way endorse or support such therapy, service, product or treatment and is not intended to replace advice from your doctor or other registered health professional. The information and materials contained on this website are not intended to constitute a comprehensive guide concerning all aspects of the therapy, product or treatment described on the website. All users are urged to always seek advice from a registered health care professional for diagnosis and answers to their medical questions and to ascertain whether the particular therapy, service, product or treatment described on the website is suitable in their circumstances. The State of Victoria and the Department of Health & Human Services shall not bear any liability for reliance by any user on the materials contained on this website.