Functional magnetic resonance imaging (fMRI) first appeared in 1991. Since that time there has been a burgeoning use of the technology by psychiatric researchers and neuroscientists. Our group first used fMRI to study obessive compulsive disorder (OCD) with a symptom provocation paradigm and then moved to the use of circuitry-specific cognitive-behavioral probes. The techniques we utilized for the symptom provocation study remain valid today, but have been supplemented by a wide array of new tools. Functional MRI continues to be a rapidly developing technology which could become the gold standard for neuroimaging research in psychiatry. With this in mind, this paper focuses on the past, present, and future applications of fMRI to one model illness, namely OCD. We examine the strengths and limitations of our initial OCD symptom provocation study and then evaluate the use of fMRI with cognitive-behavioral probes of cortico-striatal circuitry and limbic (amygdala) circuitry. We conclude with a brief summary of foreseeable developments which will influence the implementation of fMRI for psychiatric neuroscience in general.