A method and device for the identification of documents and banknotes marked with Optical Variable Inks providing: generating a white light ray between 5,000.degree. and 7,000.degree. K; polarizing that white light ray through a first polarizing filter (3), and sending the polarized ray (4) onto an area (5) to be assessed; filtering the ray (6) reflected the area (5) to be assessed by a second polarizing filter (7), in phase consistency with the first polarizing filter (3) and getting a first signal (s.sub.a); filtering the ray (6) reflected by the area (5) to be assessed by a third polarizing filter (8), in anti-phase with the first polarizing filter (3), and getting a second signal (s.sub.b); measuring the difference .DELTA. between these two signals; comparing the calculated value .DELTA. to a reference value .DELTA..sub.r previously measured on genuine documents and banknotes.