Beginning in the mid 1950s and continuing through today, the Southwest Oncology Group (SWOG) has been a leader in cancer clinical research in adults. SWOG has contributed to the field of cancer research through both the logistical development of new systems, technologies, statistical methodologies, and training, and through specific tangible contributions to science, addressing the standard of care for almost every adult malignancy. This review summarizes the highlights of SWOG contributions over the years, including contributions in medical oncology, staging, radiation oncology, surgery, and other cancer-related disciplines. © 2008 Elsevier Inc. All rights reserved.