It has taken 17 years from the first identification of a voltage-gated Ca2+ channel (CaV) beta-subunit as a band on a gel following purification of skeletal muscle dihydropyridine (DHP) receptors in 1987 to the publication of key information on the structures of Ca2+ channel beta-subunits. Three recent X-ray crystallographic studies have now solved the structures of the core domains of three Ca2+ channel beta-subunits. In this article, the properties of these cytoplasmic auxiliary subunits will first be summarized. Then the CaVbeta structures and the information they provide regarding how these proteins interact with the CaValpha1 subunit will be discussed and the possible implications of these new data for G-protein modulation of Ca2+ channels will be examined.