2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/122514We show that any normal algebraic monoid is an extension of an abelian variety by a normal affine algebraic monoid. This extends (and builds on) Chevalley's structure theorem for algebraic groups.Final version, to appear in Semigroup ForumAlgebraic Geometry14L10, 14L30, 20M20text