I'm actually not sure. Will do more research. For science.

If you'd like to form an opinion for yourself:

Hard to tell, right?

One thing's for sure: she likes shirts that are too tight for her.

Even gifs are inconclusive.

Here Salma Hayek's breasts have a natural bounce:

Here Salma Hayek's boobs unnaturally stay in place:

To be fair, it's possible she uses tape to keep her breasts immobile.

When asked whether any part of her body looked better ten years ago, Salma Hayek's surprise response was: 'My boobs'. She added: 'They're not bad, by the way. I'm not complaining about them.'

Source is this Allure interview:

http://www.dailymail.co.uk/tvshowbiz/article-2026743/Salma-Hayek-My-boobs-looked-better-years-ago--Im-complaining.html

Hmmm.

One thing's for sure: She seems to avoid bras.

Okay, now I think we're getting somewhere:

45-year-old Salma Hayek won the award for “Best Breasts” in the 2007 Anatomy Awards, and has one of the best set of boobs in Hollywood—and they’re totally real!

When she was younger, the self-confessed late bloomer revealed that she didn’t always have such large assets. But instead of turning to plastic surgery, she turned to prayer… yes, prayer. During an interview on “The Graham Norton Show,” Salma admitted:

“I was the youngest in class and all these girls were starting to get breasts and I wasn’t getting anything… I went to a church that had a saint that was supposed to do a lot of miracles. I put my hands in the holy water and went, ‘Please Jesus, give me some boobs’.”

Obviously, it worked.

There you go. The power of prayer. And yes, they're real.

Right, Salma?

Salma Hayek Breast Size 2013: At just five feet-two inches tall, Salma's breasts are 36-C, according to multiple websites, including this one:

http://healthyceleb.com/salma-hayek-height-weight-body-statistics/

One website thinks her size is 32-D:

http://www.bodymeasurements.org/salma-hayek-sizes/

And one website thinks her size is 28-G:

http://fullerfigurefullerbust.com/2012/12/11/celebrity-bra-sizes/

But all the other websites say 36-C, so that's my final answer. 

Also, this website claims that Salma Hayek did have a nose job:

Actress Salma Hayek says she hasn’t had plastic surgery and doesn’t like the looks of plastic surgery patients. But past photos of her make a strong case to the contrary. Apparently she did in fact have a nose job, may have gotten breast implants and definitely came out of those operations looking fine. Yet in the September edition of Allure magazine Hayek says that plastic surgery is “like the uniform of a generation, and it’s not necessarily beautiful.” She adds, “It’s not wrinkled-looking, but it’s not beautiful.”

I believe Salma, not the website.

You can't believe everything you read on the Internet, you know.

This source also tells it to be 36, also, she does seem to have nose job : http://www.celebdetail.com/salma-hayek-measurements-height-weight-bra-size-age/

Other "are her breasts real?" exposes coming soon. For science.