The report summarizes the discussions of a roundtable convened in Washington, DC, to share some key lessons about law enforcement-public health collaborations in addressing violence. Two presentations reviewed advancements in violence prevention methods. One presentation explained how to predict gun violence by analyzing social networking and community-level prevention strategies. The second presentation explained the use of anonymous data from emergency rooms to inform crime-fighting and community level violence-prevention strategies. Following these presentations, the jurisdictions that were awarded mini-grants from The California Endowment described their pilot projects of collaboration between law enforcement and public health professionals in the development of violence-prevention strategies. The cities involved in the pilot effort are East Palo Alto, CA; Milwaukee, WI; Chicago, IL; and Los Angeles, CA. Grant-makers then provided advice on how small projects might develop and expand. Attention was given to budget limitations, the documentation of the impact of a project, collaboration, and funding interests. Roundtable participants (police, public health experts, and grant-makers) agreed that the new partnerships between public health and law enforcement were just the beginning. Participants were interested in promoting a national-level discussion about how public safety and public health agencies might cooperate in reducing violence.