This article is a critical review of risk factors for pathological gambling categorized by demographics, physiological and biological factors, cognitive distortions, comorbidity and concurrent symptoms, and personality symptoms and characteristics. There is also a varia section (availability, parents playing, sensory characteristics, schedules of reinforcement, age of onset, and playing duration). The review found very few well established risk factors for pathological gambling (i.e. more than two studies to support the conclusions). Well established risk factors included demographic variables (age, gender), cognitive distortions (erroneous perceptions, illusion of control), sensory characteristics, schedules of reinforcement, comorbid disorders (OCD, drug abuse), and delinquency/illegal acts. An understanding of risk factors for pathological gambling should enhance prevention and treatment approaches.