Nutrition surveillance is expensive and logistically laborious and therefore often non-existent in resource-low countries. Surveillance systems are also constrained by time-consuming and error-prone paper-based data collection followed by manual data entry. Consequently, monitoring of nutrition outcomes in real time and timely response to nutritional crises is often impossible. This new evidence review Using Mobile Phones for Nutrition Surveillance by Inka Barnett and Jose V Gallegos, funded by Transform Nutrition, outlines how mobile phone technologies could help to address many of these challenges and offer potential benefits.