Epilepsy and seizures result in widespread alterations in brain function that may progress over time. Quantifying this functional reorganization can lead to a better understanding of the cognitive and behavioral symptoms associated with this disease. Furthermore, changes in brain function may serve as biomarkers of specific types of epilepsy and provide targets for treatment. Functional MRI is a powerful, non-invasive, and flexible tool to quantify various aspects of this dysfunction and reorganization. This chapter provides an overview of four strategies using functional MRI imaging in the management or investigation of epilepsy. First, fMRI cognitive mapping for quantifying epilepsy related dysfunction and predicting treatment outcomes is discussed. This is the most clinically translatable and widely used fMRI method in patients with epilepsy. Second, fMRI methods for localizing detectable epileptic activity in the brain, including simultaneous EEG-fMRI, are explained. The third section describes some of the quantitative parameters of the fMRI signal and their characteristics related to epilepsy. Finally, the fourth section introduces the concept of fMRI network mapping and its application to epilepsy. Each section contains methodological descriptions, including advantages and limitations, and potential clinical and research applications. The goal of this chapter is to illustrate the versatility of the fMRI signal in probing the widespread alterations in brain function in various types of epilepsy.