The L X-ray fluorescence cross sections (sigma(L1), sigma(L alpha), sigma(L eta), sigma(L beta), sigma(L beta 6), sigma(L beta 2,4), sigma(L beta 1,3), sigma(L beta 9,10), sigma(L gamma 1), sigma(L gamma 2,3), sigma(L gamma 4) and sigma(L gamma 5)) and relative intensities (I-L alpha, I-L1, I-L eta, I-L beta, I-L beta 6, I-L beta 2,I-4, I-L beta 1,I-3, I-L beta 9,I-10, I-L gamma, I-L gamma 1, I-L gamma 2,I-3, I-L gamma 4 and I-L gamma 5) for some elements in the atomic range 78 <= Z <= 92 have been measured at 59.54 keV photons energies from an Am-241 point source. The L X-rays emitted by samples have been counted by a Si(Li) detector. The L X-ray fluorescence cross sections and relative intensities have been also calculated theoretically by using atomic parameters. The measured values have OF been compared with the theoretical values. (c) 2007 Elsevier B.V. All rights reserved.