We have calculated the plasmon dispersion relations in a doped double quantum well with and without exchange-correlation potential added to the effective potential of the system. The calculations were done for high and low doping densities by solving the Schrodinger and Poisson equations self-consistently. Our numerical results show that the exchange - correlation potential is quite important at high doping densities of donor impurities for plasmon dispersions at large wave vectors. On the other hand, the ratio of subband populations n(i) to donor density N-D is more affected at low densities. (C) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.