The evidence for a relationship between methamphetamine use and violent behavior is broadly consistent with the hypothesis that methamphetamine use may have contributed to a rise in assaults in New South Wales (NSW) over the past decade. However, the evidence also suggests that the contribution of methamphetamine use to assaults is likely to be minor in comparison with other factors, such as alcohol. In Australia, the last decade has witnessed a dramatic rise in the popularity of crystalline methamphetamine use. During this time, there has also been increasing attention on aggressive behavior among people intoxicated with the drug. This bulletin sought to document the increase in methamphetamine use over the past decade, review the evidence that methamphetamine use increases the risk of violent behavior, understand in which circumstances methamphetamine use is likely to increase the risk of violence, evaluate the evidence, if any that the growth in methamphetamine use has contributed to the upward trend in assaults over the last decade, and identify areas where further research and monitoring is needed to understand the impact of methamphetamine use on individual violent behavior and rates of assault. Figures, references