Soybean plants of the variety ‘MG/BR Conquista’ were grown in open top chambers, simulating elevated CO 2 concentration ([CO 2 ]) and high temperature under the following treatments: 1) ambient [CO 2 ] and ambient temperature (Amb); 2) elevated [CO 2 ] (eCO 2 ) and ambient temperature (Elev); 3) ambient [CO 2 ] and high temperature (Amb/Temp); 4) elevated CO 2 and high temperature (Elev/Temp). The aim was to evaluate responses to elevated [CO 2 ] and high temperature, with focus on plant development and seed yield, and composition. Elev stimulated grain yield and Amb/Temp had opposite effect. Several biochemical parameters were affected by Amb/Temp, most of them reversed by simultaneous application of Elev. The oil obtained with Elev/Temp had lower degree of unsaturation. A network of relationships among biochemical parameters of grains at three developmental stages revealed that Amb/Temp and Elev/Temp affect significantly both carbohydrate and lipid metabolisms. No significant difference was obtained comparing networks corresponding to Amb and Elev/Temp.