The evidence that exposure to media violence causes later aggression derives largely from observational (nonexperimental) studies augmented by short-term experimental studies. The authors review some of the difficulties in causal inference from observational, longitudinal data; examine the extent to which these seem relevant to the empirical work on exposure to televised violence published to date; and present a reanalysis of data from an especially influential study to address one of the more serious limitations of existing analyses. They conclude that the data give evidence that there is likely, although not certainly, a causal connection between exposure to televised violence and adult aggression. The authors close with a brief discussion of policy interventions designed to reduce exposure to violent TV.