Excavation in a small pyramid at the lowland Maya site of Cerros has brought to light a well-preserved polychrome painted stucco façade dominated by a monumental mask. The façade constituted the first well-preserved example of Late Preclassic Maya architectural decoration exposed since discovery of Str. E-VII-sub at Uaxactun, Guatemala, in 1927. Salient details concerning the façade's context, dating and iconographic significance are reported.