On the basis of the Slovenian and foreign archive materials the author analyses and demonstrates the issues involved in the creation of the joint army of the Kingdom of Serbs, Croats and Slovenes with a special emphasis on the transfer of the former Slovenian Austro-Hungarian active and reserve officers to the joint army of the Kingdom of Yugoslavia. The transfer of the Slovenian officers to the joint army, established according to the model of the Serbian royal army under the command of Serbian high-ranking officers and with Serbian command and duty language, was difficult and quite unfair, treating the Slovenian officers unequally in comparison to their Serbian and Montenegrin colleagues. Many patriotic Slovenian officers were not even admitted to the joint army and they remained the responsibility of the Provincial Government, which tried to take care of them as well as it could.