The ferromagnetic resonance linewidth has been measured at frequencies from 9–57 kMc/sec at room temperature in bulk single-crystal samples of nickel and in thick single-crystal whiskers of iron. The results for nickel can be accounted for by relaxation damping described by a frequency-independent Landau-Lifshitz coefficient λ=2.3×108 sec−1 plus a smaller contribution from the exchange-conductivity mechanism. The widths in iron are found to vary as the square root of the frequency and are due mainly to exchange-conductivity broadening. They can be fit with exchange stiffness 1.9×10−6 erg/cm (known from other experiments), magnetic surface-anisotropy energy 0.4 erg/cm2, and Landau-Lifshitz relaxation parameter ≲0.7×108 sec−1.