Recent advances in brain imaging technologies allow researchers to “peer inside” a defendant’s brain. Although functional neuroimaging evidence is frequently used in civil litigation, federal courts have been hesitant to admit it into evidence in criminal trials. Scholars and commentators alike continue to debate the merits, detriments, and general admissibility of functional neuroimaging evidence in the criminal context. Meanwhile, federal judges repeatedly admit various forms of forensic science into evidence without evaluating them under the appropriate admissibility standards. This Note argues that this has created a double standard for evidence admissibility. Functional neuroimaging evidence may, in fact, be more scientifically reliable than some of the forensic science evidence currently admitted at trial. Accordingly, this Note proposes that judges should consider the disparity in evidentiary standards when considering the admissibility of functional neuroimaging evidence, and should carefully and fairly examine such evidence when proffered in federal criminal trials.