The results of our recent studies of the selectivity of a calcium channel by means of a Monte Carlo simulation and of the conductance of ions in a model channel by means of a molecular dynamics simulation are reported. In our selectivity study we find that as a result of the charge and confined space within the channel, Ca ++ ions are preferred over Na + ions because of their ability to deliver twice the charge using about the same excluded volume. In our conductance study, the simulation is run in parallel for a total of 100 ns for each condition of concentration and applied potential. For a 1 M NaCl solution with SPC/E water using a moderate applied voltage, 12 Na + and no Cl - ions pass through the channel. The voltage drop across the channel and the conductance are reported.