The objective of this research was to evaluate the use of the Life Cycle Assessment methodology to assist decision-making in structural projects of reinforced concrete. Were studied structural models for an eight-story building, with classes of compressive strength (fck) of concrete ranging from 25 to 50 MPa. Also, were evaluated changes in the dimensions of structural elements, as well as the consumption of component materials of the structure. Results showed that the structural models for classes C40 obtained the best results for 67% of the categories of potential impacts assessed, with potential impact values ranging from 7.4% to 21.2%, including the possibility of saving 18 thousand kg of CO2 emitted. After carrying out an economic analysis, was observed that the structural model for the C40 concrete presented the optimal environmental-economic solution. The results of this research indicate the feasibility of using the Life Cycle Assessment methodology and economic analysis as tools to assist in decision-making during the design process of reinforced concrete structures.