The identification of the epithelial Ca²⁺ channel (ECaC) complements the group of Ca²⁺ transport proteins including calbindin-D_28K, Na⁺/Ca²⁺ exchanger and plasma membrane Ca²⁺-ATPase, which are co-expressed in 1,25(OH)₂D₃- responsive nephron segments. ECaC constitutes the rate-limiting apical entry step in the process of active transcellular Ca²⁺ transport and belongs to a superfamily of Ca²⁺ channels that includes the vanilloid receptor and transient receptor potential channels. This new Ca²⁺ channel consists of six transmembrane-spanning domains, including a pore-forming hydrophobic stretch between domain 5 and 6. The C- and N-terminal tails contain several conserved regulatory sites, implying that the channel function is modulated by regulatory proteins. The distinctive functional properties of ECaC include a constitutively activated Ca²⁺ permeability, a high selectivity for Ca²⁺, hyperpolarization-stimulated and Ca²⁺-dependent feedback regulation of channel activity, and 1,25(OH)₂D₃-induced gene activation. This review covers the distinctive properties of this new highly Ca²⁺-selective channel and highlights the implications for active transcellular Ca²⁺ reabsorption in health and disease.