The earliest states developed in the central Andean highlands and along the central Pacific coast of western South America. The consensus in the archaeological literature is that state societies first developed in the central Andes in the early part of the first millennium C.E. A minority opinion holds that first-generation states developed as early as the late second millennium B.C.E. in the same area. The Andean region constitutes one of a few areas of first-generation state development in the world. This area therefore represents an important case study for the comparative analysis of state formation. This article outlines the arguments for state formation in South America, presents the evidence, analyzes the underlying assumptions about these arguments, and assesses the South American data in terms of contemporary anthropological theory of state evolution.