There is a rapidly accumulating body of knowledge related to the neurobiology of impulsiveness from multidisciplinary neuropsychological and neuroimaging studies. This paper reviews recent research on impulsiveness in the context of neuropsychological theory and research. It has been emphasized that the controversy regarding the results of neuropsychological studies is related to different aspects of impulsiveness. The term "impulsivity" is related to more than one anatomical network among several brain regions. Impaired inhibition control, which has cognitive and behavioral dimensions, has a heterogeneous nature. Analysis of performance suggests that impulsivity includes three cognitive mechanisms: "prepotent inhibition," "interruptive inhibition" and "interference control,' each having separate neurological bases. Based on neuropsychological data it has been stated that both the orbitofrontal cortex, dorsolateral prefrontal cortex and anterior cingulate cortex are functionally disturbed among impulsive individuals. Bringing together knowledge from clinical experience, neuroimaging examination and neuropsychological assessment will lead to better and wider understanding of behavioral symptoms in clinical psychiatric practice.