Unlike the MPx, the MPx100 runs Microsoft’s flavor of Windows Mobile, Windows Mobile Smartphone 2003 Edition, that has been designed for devices that are to lean more heavily towards the smartphone side of the PDA/phone equation. And unlike Motorola's current Windows Smartphone, the MPx200, the MPx200 isn't a clamshell device but uses a more traditional candy bar design. The rumored sequel to the MPx200, the MPx220 is another clamshell smartphone.

The tri-band (900/1800/1900 MHz) GSM/GPRS MPx100 combines the familiar Windows Mobile user interface with email, messaging, multimedia, and Bluetooth connectivity. The Motorola MPx100 includes Pocket Internet Explorer supporting HTML, WAP 2.0 and GPRS. It also has the standard Windows Mobile PIM and synchronization features and a joystick for navigation.

The Motorola MPx100 has 64MB or RAM, a Secure Digital slot for memory expansion, up to 512 MB, an integrated 1.3 mega pixel camera with flash and 3x zoom, Java support, and a color display. As a Windows Smartphone handset, its display has a 176x220 pixel resolution.