The results of nonlinear optical studies at 532 nm using picosecond pulses in n-type ZnSe and n-type ZnSe-doped Ag are reported. The effects of doping and annealing temperature on linear (α) and nonlinear (β) absorption coefficients as well as on the third-order susceptibility χ 3 are investigated. All the samples studied reveal a strong nonlinear absorption which decreases with an increase of annealing temperature, hence of the free electron concentration. The sample doped Ag displays absorption coefficients smaller than those of the ZnSe crystal annealed at the same temperature. The magnitude of the real part of χ 3 in n-type ZnSe crystals increases with doping.