The agricultural sector suffers the influence of various risk factors. Although there is no profit without risk, it is very important to know the risks faced and devise strategies to minimize them. In this sense, this paper proposes a new approach for risk assessment, adapting the system dynamic methodology to the study of risk in agricultural systems. From this new approach, it was possible to identify new risk factors for the maize production system in Mato Grosso, Brazil. Several simulations were carried out, in order to detect the impact of each identified variable in the profitability of the system. The most important factors influencing profitability were those that directly affect the revenues of the system, such as the exchange rate, sale price, and yield.