A finite difference solution is presented for the laminar, compressible wake behind a flat plate at zero angle of attack. The solution of the boundary layer equations is carried out in the von Mises coordinate plane. A coordinate transformation which maps the infinite region into a finite one is also introduced. The accuracy and range of validity of the asymptotic and preasymptotic theories of Goldstein and Tollmien for the incompressible wake are discussed. The effect of the Mach number and initial conditions on the evolution of the wake is investigated. The analysis is applicable outside a trailing edge region of O(LRc −3/4 ) and for a constant density-viscosity product and Prandtl number unity.