Measurements of the relative X-ray production cross sections Lalpha /Lt, Lbeta /Lalpha and Lgamma /Lalpha by relativistic electrons for the heavy elements Gd, Tm, Ta, Au, Pb, Bi and Th have been carried out. The ratios Lbeta /Lalpha , Lgamma /Lalpha and Lalpha /Ll are compared with previous experimental and theoretical work.