July 2014 — Avahan, the India AIDS Initiative of the Bill & Melinda Gates Foundation, was a large-scale HIV prevention program for key populations in six Indian states and at major stops along the national highways. Community-centered clinical services were a primary component of the comprehensive HIV prevention package offered by the program, and many innovative approaches were developed to tailor these to the needs of the key populations. This document provides case studies and shares good practices and lessons learned through the case studies. The goal of this publication is to help HIV prevention program implementers strengthen their capacity to deliver high-quality clinical services to key populations.