4,4'-Biphenol polysulfone composition comprising: as main ingredient, at least one polysulfone comprising more than 50 mol. % of recurring units formed by reacting 4,4'-biphenol with at least one sulfone monomer SM.sub.1 (B.sup.o1 PSU), more than 0.01% by weight, based on the total weight of the composition, of at least one phosphorus-containing compound chosen from organic phosphites and organic phosphonites, and at least one polysulfone comprising more than 50 mol. % of recurring units formed by reacting bisphenol A with at least one sulfone monomer SM.sub.2(B.sup.o1 A PSU). 4,4'-Biphenol polysulfone composition containing at least 60% by weight, based on the total weight of the 4,4'-biphenol polysulfone composition, of at least one B.sup.o1 PSU, said composition having a melt viscosity ratio at 410.degree. C. and at a shear rate of 50 s.sup.-1 (VR.sub.40) of below 1.20. Process which is especially well-suited to prepare the above compositions. Articles made from the above compositions or prepared by the above process.