In order to evaluate enzyme pre-treatments of chips as means of lowering the energy demand in mechanical pulping, impregnation and refining trials were performed. Wing refining showed that property development was similar to that of reference pulps in the case of pectinase and xylanase while for chips treated with mannanase a less favourable development of the tensile index was noted. Considering the highly increased possibility for enzymatic interactions reached with greater disintegration of chips it could well be that the possibilities for enzymes to attack desired fibre wall structures may have been too few even in the case of Impressafiner treated material used here.