But despite heavy television promotion, many customers don't know how to pronounce the name of the dish, writes Candice Choi at The Associated Press.
NPR also criticized the name in a satirical column, saying it's "embarrassing to say when you have to order one."
The company gave Choi clarification on the name.
"It's flah-TEE-zah," Tony Pace, Subway's chief marketing officer, told the AP.
Subway had hoped the name would help the product stand out from competitors.
But some customers on Twitter still seemed pretty confused.
.@SUBWAY Maybe I would order a Flatizza if I could pronounce it
- Ryan Gorman (@ryangorman) April 13, 2014
The @SUBWAY #Flatizza. Too funny to say and weird to pronounce. #getanewnameforit
- Steve (@NEexpatriate) April 13, 2014
I think Subway just makes commercials so people will know how to pronounce the stuff when they order it. #flatizza #youmustbejoking
- Katie Beth Groover (@mrkaybeff) April 8, 2014
Subway is a huge company. So many people had to say yes to the word "Flatizza." What are they doing?
- Shawn Ries (@shawnries) March 30, 2014