New hydroxytelechelic cis-1,4-oligoisoprenes exhibiting variable values and distributions of the hydroxyl functionality were successfully prepared. The synthesis reactions involved chemical modifications of carbonyl telechelic cis-1,4-polyisoprene, which was obtained by controlled degradation of synthetic or natural rubber. These new oligomers were reacted with toluene diisocyanate to elaborate crosslinked polyurethane elastomers. The thermomechanical properties of the prepared polyurethanes were investigated. The results show a strong relationship between the chemical structures and properties. This work mainly shows the potentiality of making new crosslinking polyurethane materials with controlled and various properties from natural rubber, a renewable resource. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: 1677-1687, 2011