Abstract: A method for tracing materials to its source through the insertion of one or more physical tracers made of one or more radioisotopes at the source or sources, and the measurement of radioactivity at the source(s), as well as latter stages of the product production process are disclosed. The radioactivity data at the insertion time, as well as at every stage in which it is measured, is securely stored in one or more databases. The material to source matching process is accomplished by reading each radioisotope's radioactivity and comparing it to the emissivity it would have if coming from a determined source which is predictable.