The article deals with the influence of the Romanian factor on the strategic planning, preparation and implementation of the offensive of the Russian army in the summer campaign of 1916 and 1917. The „Brusilovsky breakthrough” had a decisive and great impact on the determination of the final position of Romania and its accession to Entente in 1916. The zeal of the Romanian military and political leadership of Romania to the troop movement in Moldova in 1917 in turn was an additional factor in the decision of the Russian command to attack. Both attacks results are similar to that success achieved in places where it was least expected. But the end of hopes to the building on success – such as ≪Brusilov’s breakthrough≫, and advance of the Romanian-Russian troops in Mărăşti in July 1917 – contributed to the destruction and revolutionary unrest in the Russian army.