20 Pesos

Mexico's first polymer banknote series launched on this denomination in 2001, with Banco de México printing the notes in-house — an unusual arrangement, as most central banks contract polymer work to specialist firms like Note Printing Australia or De La Rue. The tactile bars at upper left were added to assist visually impaired users, though the specification itself shifted mid-series: one signature variety from 2001 shows a compressed spacing between the second and third bar, a detail that distinguishes it from otherwise identical notes and has since attracted collector attention.

The sheer number of signature combinations across just five years reflects the high turnover in Banco de México's governing board during the Zedillo-to-Fox transition period.