Probably... but it depends on what brand and model of MP3/DVD player you own.
The good news is if you're reading this webpage on your computer, you already have everything you need to enjoy OTRCAT MP3 CDs; they are guaranteed to play on your computer.
Most of the newest generation MP3/DVD player support playing OTRCAT MP3 disks, but the MP3 CDs themselves are guaranteed to play in your computer using the program WinAmp (available for free). Many MP3 players say they will play all MP3's, but simply will not play certain MP3 bitrates. Many recordings are stored as 64kps 44khz bitrate MP3 files; if your player supports these specs, they should work fine, but not always.
For away from the computer listening, see a list of recommended MP3 players or general information about the MP3 format.
See also: how to listen to old time radio in your car.
Audio disks will play in any standard modern audio CD player at home or in your car.