In the last years, risk management assumed a relevant and definitive role in the environment of financial institutions. More recently however, the subject has also been gaining ground in the environment of non- financial institutions. Among the benefits arising from the introduction of risk management within the environment of non-financial institutions, those that stand out as being the most direct are the control of the cash flow necessary for the investments that have been programmed, reduction in the volatility of this cash flow, and consequently in the probability of the company failing to honor its future commitments. Additional benefits include an increase in transparency as far as investors are concerned, a rapid assimilation of new risk sources by the managers. Considering this gap and the theme`s importance to non-financial institutions, this work proposes a theoretical model, which aims to measure firm cash flow-at-risk. Afterwards, the proposed model is applied and tested in only one Brazilian distribution electric sector company. Such a model may be able to return the probability that a company faces a financial distress, for not being able to make due payments in the set dates.