Dating to about 1500-1560, Nueva Cadiz beads are the earliest glass beads found in the Americas, and many questions regarding their technology and provenience surround them. Analysis of 10 beads from the namesake Nueva Cádiz site in Venezuela and 33 beads collected from an unknown site or sites near Tiahuanaco, Bolivia, provide chemical compositions of their turquoise, dark blue, white, red, and colorless glasses. We analyze the sand, flux, and colorants that went into their fabrication. The two collections show a common beadmaking tradition and provenience, except for three beads made of high-lime low-alkali (HLLA) glass. Colorants and opacifiers are cobalt for blue, a tin-based agent for white, and copper for turquoise and red. Trace elements associated with cobalt indicate a variable source for this colorant. By comparing the layers of composite beads, we discover technological aspects of bead design and workshop organization. To investigate provenience, we compare the levels of key elements with other glasses of proven origin. There are similarities with glasses made in Venice and Antwerp, identifying these places as candidates for the origin of Nueva Cadiz beads.