The author generalizes the classical Myers theorem to the case of a complete and connected Riemannian \(n\)-manifold \(M\) with \(m\)-Bakry-Émery Ricci tensor given by \[ \mathrm{Ric}_{V,m}=\mathrm{Ric} + \frac{1}{2}\mathcal{L}_Vg - \frac{1}{m-n}V^*\otimes V^*, \] where \(\mathcal{L}_V\) and \(V^*\) denote, respectively, the Lie derivative and the metric dual of a smooth vector field \(V\) on \(M\). It is assumed that \(m\geq n\) and that, if \(m=n\), then the vector field \(V\) is zero and the tensor above reduces to the usual Ricci tensor. Assuming certain positive lower bound on \(\mathrm{Ric}_{V,m}\), the author shows that \(M\) must be compact with diameter bounded above by a constant depending on the lower bound. The proof is based on the Riccati comparison theorem.