A microscopic method to calculate one nucleon overlap integrals for light nuclei is presented. This method is based on the solution of the inhomogeneous differential equation with a fully microscopic treatment of a source term. The source term is calculated with effective two-body nucleon-nucleon (NN) forces and many-body nuclear wave functions represented in a translation-invariant shell model basis. Such an approach automatically provides the correct asymptotic behaviour of the overlap integral. Numerical calculations have been performed for the 7 Be * n p 8 B g . s . , 7 Li g . s . n 8 Li g . s . and 1 0 Be g . s . n 1 1 Be * (12 - ) overlaps. It has been found that the spectroscopic factors, obtained as norms of the calculated overlap integrals, depend on the choice of the NN-potential and may differ strongly from the corresponding shell model values. The shapes of the overlap integrals are not very sensitive to the NN-potentials used in the calculations, and are mainly determined by the oscillator radius. The microscopically calculated overlaps are close to the two-body potential-model wave functions obtained with standard geometric parameters of the Woods-Saxon potential.