Throughout the course of history, gambling has been a popular activity across most cultures. In the United States, gambling has transitioned from early acceptance to prohibition to widespread proliferation. For most, gambling is a relaxing and recreational activity; however, for some individuals gambling becomes more than harmless fun. The most severe form of gambling, pathological gambling, is recognized as a mental health disorder. Pathological gambling is currently classified as an impulse control disorder in the DSM-IV-TR, but it shares many important features with substance use disorders, especially in terms of diagnostic criteria, clinical course, and treatment. Consequently, the DSM-V Task Force has suggested that pathological gambling be reclassified and included in a new category entitled "Addiction and Related Disorders." The category would include both substance-related and non-substance/behavioral addictions. This article provides a general overview of some of the available literature regarding pathological gambling and includes the presentation of a number of relevant topics including etiology, risk factors, comorbidity, prevention, and treatment. However, as with most complex, multifaceted, and multidimensional phenomena, more research is needed in order to improve both prevention and treatment efforts for pathological gambling.