After a brief historical review, the chapter examines some of the salient arguments and notes important original studies and complex reviews of certain aspects of the topic. The article discusses: (1) how much violence children see on television; (2) how violence is portrayed on television (socially acceptable violence, violence without pain, aspects of program and viewer that enhance the effect); and (3) the link between adolescent behavior and viewing violence in the mass media. Collectively, these studies provide strong epidemiological evidence that childhood viewing of television results in the increased risk of subsequent violence. Research connecting childhood exposure to televised violence and subsequent aggression met established criteria by which epidemiological causality can be established. Specifically, the studies establish a time sequence of variables (exposure to violence in each case predated the aggressive behavior studied); consistency, strength and specificity of association; and coherence (there are theories of childhood learning that provide an explanatory model for the observed results. Figure, references