Scholars have suspected for many years that Western Mexican metallurgy originated in the metallurgies of Central and/or South America (Arsandaux and River 1921; Meighan 1969; Mountjoy 1969; Pendergast 1962b). In the central Andes, artisans were crafting metal objects by 1500 B.C., although metal working did not come into its own until the Early Horizon (700 B.C. to 200 B.C.). Columbian metallurgy began to take shape around 200 B.C., or before; the metallurgy of lower Central America several hundred years later. In the West Mexican metalworking zone the technology was flourishing by A.D. 800, although metal objects have been recovered dating to several hundred years prior to that. The late appearance of metallurgy in West Mexico suggests that it was introduced from outside. Also, some metal artifacts form Andean South America and lower Central America and Colombia are identical in formal design to later West Mexican types. Such design similarities can signal historical connections, but they represent only one measure of them. To thoroughly explore this issue we need to investigate all aspects of the technology: the kinds of objects made and their design characteristics, the manufacturing techniques, the metals and alloys used to make them, and, where possible, their meaning in specific social contexts. The evidence, taken as a whole, unambiguously indicates that Period 1 West Mexican metallurgy is so similar to that of certain South and Central American metalworking zones that some elements of West Mexican metallurgy clearly were introduced form those areas. The metallurgies of two regions played primary roles: lower Central American and Columbia, and the southern part of the modern nation of Ecuador.