The potential due to two equal parallel circular plates when the potential is specified over them is expressed as a series of integrals involving Besseel functions. Equations for the coefficients are found in terms of the boundary values and the solutions of these are determinednumerically by iteration. Tables of these constants are given in the case of conducting plates. The capacity of the circular plates condenser and the forces between two charged plates are calculated and these are plotted in enrves against the distance between two plates