The presence of fissures in the cement material of an oil well due to thermo-mechanic conditions caused by steam injection and acidizing operations, tends to commit the mechanical integrity of the annular space, resulting in the environmental contamination of the phreatic sheets and oil producing zones. However, the development of new materials for oil wells cementing has lead to several researches to achieve the optimization of this process. This work proposes the formulation of portland/polyurethane nonionic composites as a new material for oil wells cementing. The results prove the ability of the formulated composite to improve the mechanical properties when compared with portland/water cement slurry. Also, were obtained significant improvements in mass losses when acids were present.