Dynamics of electronic excitation energy transfer iri the mono-and multilayer Langmuir-Blodgett (LB) films of 5-(4-N-octadecylpyridyl)-10,15,20-tri-p-tolylporphyrin on glass substrate has been investigated by means of picosecond time-resolved fluorescence spectroscopy using a single photon counting technique. The observed decay rate constants for the intra- and interlayer energy transfer are 1.2 x 10(9)/s and similar to 4.0 x 10(9)/s, respectively, which are consistent with the relative fluorescence quantum yield for the LB films on the glass substrate.