We have investigated the Pt-195 and C-13 nuclear magnetic resonance (NMR) spectroscopy of clean-surface platinum catalysts and of CO chemisorbed onto Pt catalyst surfaces. We use Knight shift, relaxation, and J-coupling data to deduce information about the Fermi level local density of states (E-f-LDOS) at catalyst surfaces. There is a linear correlation between the Knight shifts of chemisorbed CO and the clean surface Ef-LDOS of platinum onto which the CO is bound, as determined by C-13 and Pt-195 NMR. The correlation amounts to similar to 12 ppm/Ry(-1).atom(-1), the same as that which can be deduced for CO on palladium, as well as from the electrode potential dependence of C-13 Knight shifts and infrared vibrational frequencies, nu(CO), and the relationship between vco and the E-f-LDOS at clean platinum surfaces. The ability to now directly relate metal and adsorbate electronic properties opens up new avenues for investigating metal-ligand interactions in heterogeneous catalysis and electrocatalysis.