Natural disasters affect hundreds of millions of people worldwide every year. Emergency response efforts depend on the availability of timely information, such the movement and communication behaviours of affected populations. As such, analysis of Call Detail Records (CDRs) collected by mobile phone operators reveal new, real-time insights about human behaviour during such critical events. In this study, mobile phone activity data was combined with remote sensing data to understand how people communicated during severe flooding in the Mexican state of Tabasco in 2009, in order to explore ways that mobile data can be used to improve disaster response. By comparing the mobile data with official population census data, the representativeness of the research was validated. Cite as: "Using Mobile Phone Activity For Disaster Management During Floods", Global Pulse Project Series no. 2, 2014