Hydroxy-terminated polyoxymethylene-co-polyoxyalkylene multi-block telechels were obtained by a new methodology that allows for the formal substituting of ether units in polyether polyols with oxymethylene moieties. An interesting feature is that, unlike carbonate groups in polycarbonate and polyethercarbonate polyols, homopolymer blocks of polyoxymethylene moieties can be formed. The regular nature of polyoxymethylene blocks imparts a certain crystallinity to the polymer that can give rise to new properties of polyurethanes derived from such telechels. The synthesis, reaction sequence and kinetics of the formation of oligomeric hydroxy-terminated multi-block telechel polyoxymethylene moieties are discussed in this paper and the preparation of a polyurethane material is demonstrated.