  Next to leading order effective field theory calculations are performed for $
{}^1S_0$ NN scattering using subtractive renormalization procedure. One pion
exchange and contact interaction potentials are iterated using
Lippman-Schwinger equation. Satisfactory fit to the Nijmegen data is obtained
for the momenta up to 300 MeV in the centre of mass frame. Phase shifts are
also compared with the results of KSW approach where pions are included
perturbatively.
