Let b ≥ 2 be an integer. We prove that the b-ary expansion of every irrational algebraic number cannot have low complexity. Furthermore, we establish that irrational morphic numbers are transcendental, for a wide class of morphisms. In particular, irrational automatic numbers are transcendental. Our main tool is a new, combinatorial transcendence criterion. 1. Introduction Let b ≥ 2 be an integer. The b-ary expansion of every rational number is eventually periodic, but what can be said about the b-ary expansion of an irrational algebraic number? .