Let \(\tau\) denote the stress tensor and \(u\) the velocity vector. In case of Oldroyd-B fluids one has the law \(\tau+ \lambda_1 \frac{D_{\alpha} \tau}{Dt}= 2 \eta \left[D(u) + \lambda_2 \frac{D_{\alpha}D(u)}{Dt} \right]\), where \(D(u) = \frac 12 [\nabla u + (\nabla u)^T]\), the operator \(D_{\alpha}\) is defined via \(\nabla u\) and \((\nabla u)^T\). The above law yields a system of partial differential equations which coincides with the Navier-Stokes equations for \(\lambda_1=\lambda_2=0\). The authors show that the initial-Dirichlet problem in an exterior domain \(\Omega \subset \mathbb R^n\) has a unique solution in a certain functional space provided the initial data and the coupling constant are small enough.