In addition to their well characterized interaction with the alpha 1 subunit of the voltage-dependent L-type Ca2+ channel, certain Ca2+ antagonists have been reported to modulate an increasing number of cellular functions as diverse as extrusion of cytotoxic substances, or cleavage of cAMP by phosphodiesterase. Some of these interactions (such as the reversal of multidrug resistance by Ca2+ antagonists for the treatment of lymphoma patients) have already been exploited clinically; some (such as protection of ischemic tissue by Ca2+ antagonists interacting with mitochondrial sites) open new therapeutic issues. In this survey of the non-L-type channel Ca2+ antagonist target structures known to date, Gerald Zernig evaluates the available data and emphasizes common characteristics shared by the seemingly diverse target structures. Research on these sites might help to understand yet unexplained effects of Ca2+ antagonists and possibly lead to the development of novel drugs with higher selectivity for non-L-type Ca2+ channel structures.