We present theoretical analysis of bromine adsorption on the Ge(001)-p(1×2) surface. Bromine adsorbs dissociatively at the Ge(001) surface and the adlayer of bromine develops ordered structures of adatoms bound to substrate dimers. We analyse atomic configurations of the Ge(001) surface covered by 0.25, 0.5, 0.75 and 1 monolayer of bromine. Various stable surface structures, found in calculations, are presented and their energies are compared. Simulated STM images are also discussed for the considered configurations.