The expansion of the voltage-gated calcium channel alpha 1 subunit families (CACNA1) of L and N types was investigated by combining phylogenetic analyses (neighbour-joining and maximum likelihood) with chromosomal data. Neighbouring gene families were analysed to see if the chromosomal regions duplicated through whole genome doublings in vertebrates. Results show that both types of CACNA1 expanded in two ancient whole genome duplications as parts of larger genomic regions. Many gene families in these regions obtained copies in an additional teleost-specific genome duplication. This diversification of CACNA1 genes probably contributed to evolutionary innovations in nervous system function.