Oligocarbonate diols due to their resistance to oxidation and hydrolysis are particularly valuable components of polyurethanes for biomedical applications. It was shown that for their synthesis "green monomer," ethylene carbonate can be used in the reaction with 1,6-hexanediol, instead of usually applied toxic and harmful phosgene. Depending on reaction conditions, besides ester exchange leading to the desired product, competitive etherification is often observed. To optimize the reaction conditions leading to oligocarbonates of high molecular weight without oxyethylene fragments, the method of an experimental design was applied. Such approach enabled the estimation of the influence of reaction temperature, ethylene carbonate to 1,6-hexanediol molar ratio and catalyst (NaCl) concentration on the molar mass of oligocarbonate diol, content of ether bonds and reaction time. Application of central composite method as an experimental design allowed not only to choose the optimal set of conditions, but also the coefficients of the regression equation were interpreted in a chemical way. Oligocarbonate diols obtained under optimal conditions were used for synthesis poly(urethane-urea)s which exhibited very good mechanical properties (tensile strength 45-50 MPa and elongation at break up to 500%). (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 120: 683-691, 2011