Content Notice:  This site contains HIV or STI prevention messages that may not be appropriate for all audiences. Since HIV and other STIs are spread primarily through sexual practices or by sharing needles, prevention messages and programs may address these topics. If you are not seeking such information or may be offended by such materials, please exit this website.

Sexually Transmitted Diseases

Sexually transmitted diseases (STIs), also known as sexually transmitted infections or STIs, are very common. More than 75 new infections are recorded in Montana every week. 

STIs are passed from one person to another through sexual activity including vaginal, oral, and anal sex. They can also be passed from one person to another through intimate physical contact, such as heavy petting, though this is not very common.

Many people with an STI don't know it, because they often have no symptoms. Are you having sex? Go to  to find a private, confidential, and free or low cost testing location near you.  If you are diagnosed with an STI, know that all can be treated with medicine and some can be cured entirely.

STIs are preventable. If you have sex, know how to protect yourself and your sexual partner from STIs.


Chlamydia is the most commonly reported STI in Montana and the United States. While it often has no symptoms, it can eventually cause serious reproductive damage, particularly in women.
Where to find out if you have chlamydia.


  Gonorrhea is a common infection, and if left untreated, can cause serious and permanent health problems. Often, women don’t have symptoms, and spread the infection to others unknowingly.

Find out if you are at risk for gonorrhea.


Syphilis is another serious STI that is easy to miss in the earliest stage, but is easy to cure with the right medication. During pregnancy, syphilis is very harmful to a growing fetus. Without treatment, syphilis causes serious damage throughout the body.

Learn more about protecting yourself from syphilis

HIV, the virus that causes AIDS

  There are many ways to protect yourself from HIV, even if your partner is HIV+. Abstinence, condoms and daily medication are just a few. Pre-exposure prophylaxis or PrEP is a daily pill you can take to greatly lower your risk of contracting HIV.

Learn more about preventing HIV.


How often should I get tested for HIV or STIs?

If you are sexually active, getting tested for STIs is one of the most important things you can do to protect your health. Have an open and honest conversation about your sexual history and STI testing with your doctor and ask whether you should be tested for STIs. If you are not comfortable talking with your regular health care provider, there are clinics throughout Montana that offer confidential and free or low-cost testing. Find one near you at

  • All adults and adolescents from ages 13 to 64  should be tested at least once for HIV.
  • Annual chlamydia screening of all   sexually active women  younger than 25 years, as well as older women with risk factors such as new or multiple sex partners, or a sex partner who has a sexually transmitted infection
  • Annual gonorrhea screening for all   sexually active women  younger than 25 years, as well as older women with risk factors such as new or multiple sex partners, or a sex partner who has a sexually transmitted infection.
  • Syphilis, HIV, and hepatitis B screening for   all pregnant women, and chlamydia and gonorrhea screening for at-risk pregnant women starting early in pregnancy, with repeat testing as needed, to protect the health of mothers and their infants.
  • Screening at least once a year for syphilis, chlamydia, and gonorrhea for   all sexually active gay, bisexual, and other men who have sex with men (MSM). MSM who have multiple or anonymous partners should be screened more frequently for STIs (e.g., at 3-to-6 month intervals).

Anyone who has unsafe sex or shares injection drug equipment  should get tested for HIV at least once a year.

But I don’t have any symptoms.

It’s good you don’t have symptoms. But it doesn’t mean you are free from infection. Many people who are infected have no idea anything is wrong. Meanwhile they can pass the STI on to others and can suffer serious damage to their reproductive system. Click on one of the specific STIs above,  for more information.

3 Ways to Talk With Your Partner(s) About STIs

1. Have the conversation

2. Let us do it.

If you are diagnosed with syphilis, gonorrhea or chlamydia (and some other communicable diseases), your county health department is required to ask for the names and contact information of sexual partners. Without using your name, experienced staff will contact them to offer testing and treatment. Your name and medical information is private and confidential, even if you see the same provider.

3. Resources for Health Providers

STI and HIV Screening Recommendations    
CDC Partner Services
Update to CDC's Treatment Guidelines for Gonococcal Infection, 2020
CDC’s 2021 STI Treatment Guidelines and other resources for providers
Montana Annotated Codes (MCA) STI Statutes

To report an STI, follow this link

Have you been exposed to HIV or an STI?

Case Reporting

Find a testing site near you


Contact Us

Cogswell Building
Room C-211
1400 Broadway
Helena, MT 59620
(406) 444-3565