We study the pressure-induced metal-insulator (MI) transition in ytterbium using EPR measurements with Eu as the probe for magnetic resonance. For a given pressure the linewidth ?H increases linearly with temperature indicating a Korringa type of relaxation of the Eu impurities by the conduction electrons of the host. With increasing pressure d?H/dT decreases becoming very small at a critical pressure Pc 12.5 kbars. Close to Pc, d?H/dT decreases linearly with (P - Pc) in agreement with the scaling theory for density-driven metal-insulator transitions. To the best of our knowledge, this is the first time such transitions are studied by magnetic resonance.