Research teams in the HIV Prevention Section work on a variety of projects with the goal of improving HIV health in San Francisco. The Substance Use Research Unit investigates interventions designed to reduce the risk HIV infection among populations bearing the greatest burden of disease. The Implementation Science and Evaluation Unit and Clinical Prevention Unit explore new ways to deliver and measure HIV public health programs. This work complements other HIV research programs within the San Francisco Department of Public Health and benefits our community by generating new prevention strategies tailored to the local epidemic. At the same time, through sharing of results with outside agencies and scientists. this work can benefit other communities affected by HIV.