We at the Electrical and Computer Engineering in Medicine Group (ECEM) at the University of British Columbia, Vancouver, Canada, plan to make pulse oximetry available to resource poor countries by designing a low-cost, battery-powered pulse oximeter device. We have developed the Phone Oximeter, which uses a mobile phone to compute and analyze the information received from a pulse oximeter sensor. The use of mobile phones as patient monitors is appealing as they are widely available in many developing countries. Utilizing battery power, mobile phones do not rely on a continuous source of electricity. This is essential, as most low-resource settings lack adequate infrastructure and thus cannot provide the uninterrupted power supply required for conventional patient monitoring. Furthermore, a mobile phone has the efficiency, integrated display, and processing power required to analyze and store the data derived from the pulse oximeter sensors. Data from the pulse oximeter can be transmitted to referral centers for diagnostic and advisory purposes where cellular and networking services permit.