Most adults should start colonoscopy screening at age 45 if they are at average risk for colorectal cancer, and continue regularly until about age 75, but people with higher risk often need to start earlier and screen more often.

Short answer

  • Average-risk adults: start routine colonoscopy at 45, typically every 10 years if results are normal.
  • Higher-risk adults (family history, certain diseases, genetic syndromes): often start earlier, sometimes 40 or even younger, or 10 years before the age a close relative was diagnosed.
  • Most people can stop routine screening around 75, but this depends on overall health and past results.

You should confirm your personal start age and schedule with your own doctor, because individual risk factors can change the plan.

Why 45 is now the usual start age

Health organizations such as the U.S. Preventive Services Task Force and the American Cancer Society now recommend starting colorectal cancer screening at 45 for average-risk adults because cancers are increasingly being found in people in their 40s. This change is relatively recent; 50 used to be standard, but newer data showed a rise in “early-onset” colorectal cancer (before age 50), pushing guidelines earlier.

Colonoscopy is often called the gold standard because it can both find cancer early and remove precancerous polyps during the same procedure, which can actually prevent cancer from developing.

Who is “average risk” vs “high risk”?

Average risk (most people)

You are usually considered average risk if you:

  • Have no personal history of colorectal cancer or advanced polyps.
  • Have no inflammatory bowel disease (like ulcerative colitis or Crohn’s affecting the colon).
  • Have no known hereditary cancer syndrome (such as Lynch syndrome or familial adenomatous polyposis).
  • Do not have a strong family history of colorectal cancer or advanced polyps in close relatives.

For this group, many guidelines suggest:

  • Start at age 45.
  • Colonoscopy every 10 years if results are normal (other test options exist, but colonoscopy is the most comprehensive).

Higher-risk groups (may need earlier and more frequent screening)

You may need to start before 45 and screen more often if you have:

  • A first-degree relative (parent, sibling, or child) with colorectal cancer or advanced polyps, especially if they were diagnosed before 60.
  • Multiple family members with colorectal cancer or advanced polyps, even if diagnosed later.
  • Known genetic syndromes like Lynch syndrome or familial adenomatous polyposis.
  • Long-standing inflammatory bowel disease involving the colon.
  • Certain racial or ethnic backgrounds that may carry higher risk; for example, some experts recommend earlier screening in some Black populations.

A common rule of thumb doctors use:

  • Start colonoscopy at 40 or 10 years before the age at which your youngest affected first-degree relative was diagnosed, whichever comes first.

Example:

  • If your parent had colon cancer at 45, you may be advised to start at 35.

How often to get a colonoscopy

For average-risk adults with a normal colonoscopy:

  • Every 10 years from 45 to about 75 is typical.

If polyps are found, or if you’re high risk, your interval may change:

  • 3–5 years is common after certain types or numbers of polyps.
  • Even shorter intervals in some genetic or inflammatory conditions.

Your doctor will give a personalized follow-up schedule based on what they see.

When to stop colonoscopy

Most guidelines suggest:

  • Routine screening from 45 through 75 if you’re in reasonably good health.
  • Between 76 and 85, screening becomes more individualized, depending on your overall health, prior colonoscopy findings, and life expectancy.
  • After about 85, screening is usually not recommended, because potential risks and burdens usually outweigh the benefits.

If a healthy 76-year-old has never been screened, many doctors will still consider starting screening, because the benefit could be meaningful.

What if you’re younger than 45?

Even if you are under 45, you should talk to a doctor about colonoscopy (or at least some form of screening) if you:

  • Have a strong family history of colorectal cancer or advanced polyps.
  • Have symptoms like blood in your stool, unexplained iron-deficiency anemia, persistent change in bowel habits, or unexplained weight loss.
  • Have inflammatory bowel disease affecting the colon.
  • Have been told you carry a hereditary cancer syndrome.

Early-onset colorectal cancer is rising, and some experts are actively debating whether certain groups should begin screening as early as 40, but population-wide guidelines still center on 45 for average-risk adults.

Quick FAQ style rundown

1. What age to get a colonoscopy if I’m healthy with no family history?

  • Age 45 is the recommended starting point for most average-risk adults, with repeat every 10 years if normal.

2. What if I have a parent or sibling with colon cancer?

  • Often age 40 or 10 years before that relative’s diagnosis age, whichever is earlier, with more frequent follow-up.

3. Can I choose another test instead of colonoscopy?

  • Yes, stool-based tests and imaging tests exist, but colonoscopy remains the most complete option and is often preferred, especially if risk is higher or results are abnormal on other tests.

4. Is it still useful after 75?

  • Sometimes, especially if you are healthy and have never been screened before, but this is a case-by-case decision.

A simple example scenario

Imagine a 46-year-old with no major health issues and no family history of colorectal cancer.

  • They would usually be considered average risk and should already have had (or be scheduling) their first colonoscopy around 45, then repeat in 10 years if everything is normal.

Now imagine a 38-year-old whose mother had colon cancer at 48.

  • This person might be advised to start at 38 (10 years earlier than the mother’s diagnosis) and repeat more often depending on findings.

Bottom note

Information shared here reflects public health guidelines and expert commentary published in recent years and may evolve as more data come in.

Information gathered from public forums or data available on the internet and portrayed here. To give you more tailored guidance, can you share your age and whether any close relatives have had colon or rectal cancer or colon polyps?