Skip to the content
Peabody ParentsTalk, play, read and grow, from day one

When do babies coo?

The CDC's milestone checklist lists “Makes sounds like “oooo”, “aahh” (cooing)” by 4 months, along with making sounds back when you talk. By 2 months it lists “Makes sounds other than crying.” Most babies (75% or more) do these by those ages. If your baby isn't making sounds by then, ask your pediatrician.

Checked October 29, 2026.

What the CDC's checklists say

Milestones from the CDC's “Learn the Signs. Act Early.” checklists, word for word
ByThe CDC's milestoneMonth page
2 monthsMakes sounds other than cryingYour baby at 2 months
4 monthsMakes sounds like “oooo”, “aahh” (cooing)Your baby at 4 months
4 monthsMakes sounds back when you talk to himYour baby at 4 months

Each row is from the CDC's checklist for that age (2 months, 4 months), checked October 29, 2026.

What “by 4 months” means

Developmental milestones are things most children (75% or more) can do by a certain age. The CDC puts each milestone at the age by which at least 75% of children would be expected to do it, so that even one missing milestone leads to a conversation with the doctor instead of “wait and see”. So “by 4 months” isn't an average. Many children do it sooner, and the checklists don't list everything a child learns.

What it can look like

Soft vowel sounds, often when your baby is calm and looking at you, and sounds back when you talk.

What helps

  • Copy the sound: when your baby says "ooo", say "ooo" back, then wait for their turn.
  • Talk through your day out loud. Your voice is what they're learning from.
  • Sing a short song and leave a gap at the end of each line.

Talk to your pediatrician if…

Your baby isn't doing this by 4 months, the age on the CDC's list, has lost a skill they once had, or you're worried for any reason.

You know your child best. Don't wait. If your child is not meeting one or more milestones, has lost skills he or she once had, or you have other concerns, act early. Talk with your child's doctor, share your concerns, and ask about developmental screening.

If you or the doctor are still concerned, the CDC says to ask for a referral to a specialist, and to call your state's early intervention program (find the number on the CDC's list). You do not need to wait for a doctor's referral or a medical diagnosis to make this call. If your child is younger than 3 years old, contact your local early intervention system.

More from the CDC: Concerned about your child's development? If your child seems unwell, call your pediatrician, or 911 in an emergency.

Sources