A research programme, with the objective to manufacture optical surfaces with a very low X-ray scattering level by means of the epoxy replica technique, has been carried out. X-ray scattering measurements at 44, 13.3 and 8.3 X on a variety of optical surfaces down to a r.m.s. roughness of about 2.0 X, have been performed and results are presented. The dependence of the measured X-ray scattering level on various replica production parameters, i.e.: master surface roughness, epoxy curing temperature, epoxy thickness and substrate surface roughness are discussed.