The distribution of internal shear stresses in a 2-dimensional dislocation system was investigated for the case where an external shear stress was applied. This problem served as a continuation of previous work by Csikor & Groma (2004), where an analytical result was given for the stress distribution function at zero applied stress. Firstly, the internal stress distribution generated by a set of randomly positioned ideal dislocation dipoles was studied. Analytical calculations were carried out for this case. The theoretical predictions were checked by numerical simulation; revealing perfect agreement. It was found that, for real relaxed dislocation configurations, the role of dislocation multipoles could not be neglected, but the theory could still be applied. The Probability Distribution of Internal Stresses in Externally Loaded 2D Dislocation Systems. P.D.Ispánovity, I.Groma: Journal of Statistical Mechanics, 2008, P12009