A wireless data acquisition system based on MSP430F149 is developed for the measurement of microbial fuel cells’ voltage. The main function of this system is to convert the analog input voltage into digital output code, process the digital code, and transfer the data through the GSM network or the USB interface. The core of the data acquisition device is a 16-bit general purpose Texas Instruments ultralow-power microcontroller MSP430F149. As the voltage of a microbial fuel cell is very low, the A/D converter circuit is specifically designed for high precision and high accuracy. A real-time clock is used to achieve timing measurement and the time interval can be set to meet demands. The data collected is transferred through the GSM network. Besides, a Windows environment application developed with Visual C++ can be used to access the data stored in the flash memory through USB interface.