Wiener-Hammerstein systems consist of two linear dynamic systems placed around a static nonlinearity. These models are difficult to identify due to the presence of two dynamic systems. Usually, a nonlinear estimation procedure is necessary to estimate the parameters of the different parts. This nonlinear estimation procedure needs good starting values to converge quickly and/or reliably to a global minimum. This paper proposes a method to compute a first estimate based on one measurement record only.