Abstract. In this paper, we establish analyticity of the Navier-Stokes equations with small data in critical Besov spacesḂ 3 p −1 p,q . The main method is so-called Gevrey estimates, which is motivated by the work of Foias and Temam [19]. We show that mild solutions are Gevrey regular, i.e. the energy bound ep,q ), globally in time for p < ∞. We extend these results for the intricate limiting case p = ∞ in a suitably designed E∞ space. As a consequence of analyticity, we obtain decay estimates of weak solutions in Besov spaces. Finally, we provide a regularity criterion in Besov spaces.