Cassava is the second most important root crop in the world. Despite the importance of cassava as a staple crop, little have been done to improve its productivity. Traits like early bulking and fast root growth might secure high productivity in cassava. However, it is not possible to monitor in the field how roots develop in a non-destructive way. For this reason, we tested the application of ground penetrating radar (GPR) to non-destructively monitor the growth of cassava storage roots. We also evaluated if the GPR data can be used to predict root biomass. Additionally, we wanted to understand how the growth of cassava roots are going to be affected by the increase of elevated [CO2] and to evaluate if the GPR data can detect those changes. We grew cassava in the Cassava by Free Air CO2 Enrichment experiment (CassFACE) for four months. We screened the roots of three African cassava cultivars during 2017 and 2018 field seasons. In both years, we collected data at three different root developmental stages. Destructive harvests of the storage roots were performed directly after GPR scans to calibrate the GPR determinations. The volume of the roots obtained from the GPR data presented good correlation with the weight of the roots. We also performed correlations between other GPR indices that has been used to correlated GPR data with biomass and evaluated which one can be a better estimate. This research demonstrate that GPR can be successfully use to non-destructively phenotype storage roots and tubers in the field.