Fluorescence anisotropy decay in the presence of forward and back energy transfer is studied for thodamine 6G (donor)-rhodamine B (acceptor) rigid system. Experimental data are compared with the results of Monte-Carlo simulations. Good agreement between experimental data and Monte-Carlo simulations has been obtained. Monte-Carlo simulation of emission anisotropy is performed using an originally elaborated by us hybrid method, which is characterized by much better accuracy and little time consumption. (c) 2007 Elsevier B.V. All rights reserved.