A guy can get chlamydia through vaginal, anal, or oral sex without a condom with someone who has the infection. That’s the only way it spreads. Chlamydia is caused by a bacterium that lives in the mucous membranes of the genitals, rectum, and throat, and it passes from one person to another through direct sexual contact with an infected area.
How Chlamydia Spreads to Men
The bacterium that causes chlamydia needs direct contact with mucous membranes to transmit. For men, the most common route is unprotected vaginal sex with an infected partner. During intercourse, the bacterium can infect the urethra (the tube you urinate through), which is the most frequent site of infection in men.
Anal sex is another transmission route. A man who is the receptive partner can develop a rectal chlamydia infection. A man who is the insertive partner can pick up a urethral infection from an infected partner’s rectum. Oral sex can also transmit chlamydia in both directions: receiving oral sex from someone with a throat infection can lead to a urethral infection, and giving oral sex to an infected partner can cause a throat infection.
You do not need to ejaculate or receive ejaculation for transmission to occur. The bacterium transfers through contact with infected tissue, not exclusively through semen or other fluids. This is why any unprotected genital, anal, or oral contact carries risk.
What Chlamydia Cannot Be Spread Through
Chlamydia does not spread through casual contact. You cannot get it from sharing a toilet seat, swimming pool, hot tub, towel, or clothing. Hugging, kissing, and shaking hands do not transmit it. The bacterium is fragile outside the body and cannot survive on surfaces.
Why You Might Not Know Your Partner Has It
One of the biggest risk factors for getting chlamydia is simply not knowing your partner is infected. Most people with chlamydia have no symptoms at all. This is true for both men and women, which means your partner can pass it to you without either of you realizing there’s an infection present. This silent transmission is a major reason chlamydia is the most commonly reported bacterial sexually transmitted infection.
When symptoms do appear in men, they typically show up one to three weeks after exposure. The most common signs include a burning sensation during urination, discharge from the penis, and sometimes pain or swelling in one or both testicles. Rectal infections may cause pain, discharge, or bleeding from the rectum, though many rectal infections produce no symptoms either. Throat infections from chlamydia rarely cause noticeable symptoms.
Infection at Different Body Sites
Chlamydia doesn’t just infect one area. Depending on the type of sexual contact, a man can be infected in the urethra, the rectum, or the throat, and it’s possible to be infected at more than one site simultaneously. Each site requires its own test. A standard urine test, for example, will detect a urethral infection but will miss a rectal or throat infection entirely. If you’ve had anal or oral sex, let your provider know so the right sites get swabbed.
Risk Factors That Increase Your Chances
Several factors raise the likelihood of contracting chlamydia. Having multiple sexual partners increases your overall exposure. Being under 25 is a significant risk factor, as infection rates are highest in younger age groups. Men who have sex with men face elevated risk for both urethral and rectal infections. A previous chlamydia infection does not give you any immunity, so you can be reinfected every time you’re exposed.
Reinfection is surprisingly common. In one study tracking patients after successful treatment, about 17% were reinfected with the same bacterium within six months. This often happens when a partner isn’t treated at the same time. The bacterium bounces back and forth between partners: you get treated, have sex with your untreated partner, and get infected again.
How Condoms Reduce the Risk
Condoms are highly effective at preventing chlamydia when used correctly and consistently. Proper use reduces the risk of transmission by more than 90% for infections like chlamydia. The key phrase is “correctly and consistently,” meaning every time, from start to finish. Condoms work because they create a physical barrier between the mucous membranes where the bacterium lives and the tissue it would infect.
For oral sex, dental dams and condoms also reduce risk, though they’re used less frequently in practice. If you’re not using barrier protection, regular testing is your best line of defense for catching an infection early.
When and How to Get Tested
If you think you’ve been exposed, timing matters. Chlamydia testing is most reliable when done at least one week after the potential exposure. Waiting two weeks catches nearly all infections. Testing too early can produce a false negative because the bacterial load hasn’t built up enough to detect.
For most men, the standard test is a urine sample. No swab is needed for a urethral infection. Rectal and throat infections require a swab at each site. The test itself uses a highly sensitive method that detects the bacterium’s genetic material, so results are very accurate when the timing is right.
Chlamydia is fully curable with antibiotics. Treatment is straightforward, and symptoms (if you had any) typically resolve within a week or two. The important step after treatment is making sure your sexual partner or partners also get tested and treated. Without that step, reinfection is likely. Most guidelines recommend retesting about three months after treatment to confirm you haven’t been reinfected.