The method of selective photoionization of individual subshells by monochromatized synchrotron radiation has been employed to measure independently all Coster–Kronig and fluorescence yields of the La and Pr L subshells. The energy of the primary radiation was set at approximately 50 energy points in the range of the L edges. At each setting, the induced L fluorescence radiation was recorded by a Si(Li) detector. A foil of Ti was used for normalization purposes and the Ti K fluorescence lines were also recorded with the same solid state detector. Fitting the measured fluorescence intensities vs. primary energy with the photoelectric cross-sections derived the Coster–Kronig coefficients and fluorescence yields. The obtained yields were compared with tabulated data and a good agreement among them was found.