A method for thick target PIXE analysis, which takes into account secondary fluorescence effects is presented. This simple, though approximate method yields results which are within 1% of a much more elaborate rigorous calculation. Examples are calculated for a proton energy of 1.4 MeV. The energy dependence of secondary X-ray yields is shown for some samples. The standard deviation of the results due to uncertainties in input data is ±4% for K-K excitation between 20 ⩽ Z ⩽ 30, but is otherwise worse. The proposed method was inserted into the algorithm used for the analysis of measured X-ray yields and tested on some alloys, where strong secondary effects were expected.