Abstract Dynamic characterization of materials is a complex process that usually requires expensive experimental tests. One of the most used experimental techniques for dynamic characterization of materials is the Split Hopkinson Pressure Bar test (SHPB). This technique allows to identify the stress-strain relationship of materials under high strain rates by subjecting the testing material to pulse stresses. This paper presents the formulation and solution of a first class inverse problem for the determination of the Cowper-Symonds material model parameters from a single SHPB test. The inverse problem is formulated as an optimization procedure in which a genetic algorithm determines the optimal set of material constants. The proposed characterization procedure shows advantages in the characterization process of dynamic events since the material constants are determined simultaneously and using a single SHPB test.