Load flow formulations for direct current almost always are considered into the framework of integrated Alternating Current/Direct Current (AC/DC) power systems, but generally these formulations do not include the presence of loads and multiple generators in the DC power system. In this paper, the power flow problem for DC power systems is formulated and solved. The resulting nonlinear equations are solved by the Newton Raphson Method. Also, it is discussed the inclusion of several controlled voltage nodes and their treatment is described. The developed algorithm has been proven through an illustrative example with a five-node power system. Finally, concluding remarks of the algorithm developed are pointed out, and future work in this field is suggested.