Decision-making not only requires agents to decide what to choose, but also how much information to sample before committing to a choice. Previously established frameworks for economic choice argue for a deliberative process of evidence accumulation across time. These tacitly acknowledge a role of information sampling, in that decisions are only made once sufficient evidence is acquired, yet few experiments have explicitly placed information sampling under the participant's control. Here, we use functional MRI to investigate the neural basis of information sampling in economic choice, by allowing participants (n=30, sex not recorded) to actively sample information in a multi-step decision task. We show that medial frontal cortex (MFC) activity is predictive of further information sampling prior to choice. Choice difficulty (inverse value difference, keeping sensory difficulty constant) was also encoded in MFC, but this effect was explained away by the inclusion of information sampling as a co-regressor in the general linear model. A distributed network of regions across prefrontal cortex encoded key features of the sampled information at the time it was presented. We propose that MFC is an important controller of the extent to which information is gathered before committing to an economic choice. This role may explain why MFC activity has been associated with evidence accumulation in previous studies, in which information sampling was an implicit rather than explicit feature of the decision.SIGNIFICANCE STATEMENTThe decisions we make are determined by the information we have sampled prior to committing to a choice. Accumulator frameworks of decision-making tacitly acknowledge the need to sample further information during the evidence accumulation process until a decision boundary is reached. However, relatively few studies explicitly place this decision to sample further information under the participant's control. In this fMRI study, we find that medial frontal cortex (MFC) activity is related to information sampling decisions in a multi-step economic choice task. This suggests an important role of evidence representations within MFC may be to guide adaptive sequential decisions to sample further information, before committing to a final decision.