In this thesis, we develop the theoretical and numerical foundations for a self-consistent model for the simulation of the properties of ion channels - their conductivity and selectivity - from their structure. We begin by revising the one-dimensional theory of the ionic current by setting up the self-consistent coupled Langevin Poisson equations in one-dimension, as a prototype of the three dimensional simulations. The solution of a one-dimensional approximation of the Poisson's equation for a channel modelled as a long and narrow cylindrical tube is derived. Using this solution, we calculate the ion trajectory as it traverses the channel.