This study assessed the potential use of mobile phone data as a proxy for food security and poverty indicators. It was conducted jointly with the UN World Food Programme (WFP), Université Catholique de Louvain in Belgium and Real Impact Analytics (a Belgian data analytics company). Data extracted from airtime credit purchases (or “top-ups”) and mobile phone activity in an East African country was compared to a nationwide household survey conducted by WFP at the same time. Results showed high correlations between airtime credit purchases and survey results referring to consumption of several food items, such as vitamin-rich vegetables, meat or cereals. These findings demonstrated that airtime credit purchases could serve as a proxy indicator for food spending in market-dependent households. In addition, models based on anonymised mobile phone calling patterns and airtime credit purchases were shown to accurately estimate multidimensional poverty indicators. This preliminary research suggested that proxies derived from mobile phone data could provide valuable real-time information on the levels of several indicators related to food security, which could be integrated with early warning and monitoring systems, filling data gaps between survey intervals, and in situations where timely data is not possible or accessible.