In this study, L X-ray fluorescence (XRF) cross-sections of elements with atomic number 41 ≤ Z ≤ 49 were theoretically calculated according to different excitation energies. Also, the Coster-Kronig (CK) enhancement factors observed as a result of the effect of non-irradiated Coster-Kronig transitions on L X-ray fluorescence cross-sections were theoretically calculated at different excitation energies. The change of both L XRF fluorescence cross-sections and the Coster-Kronig enhancement factors against energy were examined. The results obtained were compared with the values in the literature.