the present invention relates to a process for preparing , by condensation , copolymers having polyamide blocks and polyether blocks in which polyamide blocks having dicarboxylic chain ends are mixed with : a polyether having two oh chain ends , and a polyol having at least 3 oh functions . the copolymers have a higher molecular weight , higher mechanical properties , remain linear or only weakly branched . the multifunctionality of the polyol is only used for kinetic aspects . as regards the process , there is a reduction of cycle time , reduced technical requirements on the catalyst and vacuum system and a reduction of degradation which means a better colour stability . the invention also relates to these copolymers having polyamide blocks and polyether blocks and comprising in its chain the residues of a polyol having at least 3 oh functions .