Voltage-dependent Ca2+ channels serve as the only link to transduce membrane depolarization into cellular Ca"-dependent reactions. A wide variety of chemical substances that have the ability to modulate Ca2+ channels have been demonstrated both for their clinic utility and for importance in elucidating the molecular basis of various biological responses. Recently, introduction of molecular biology to pharmacology has brought a great deal of information about the molecular basis of drug action in Ca2+ channels. In this review, we attempt to overview recent progress in understanding the interactions between Ca 2+ channels and their blockers, namely Ca2+ antagonists, from a molecular and structural point of view.