Universal conscription and compulsory military service was imple mented in Serbia in 1883. This move was drowned relatively earlierthen in the most of European countries and transformed from scared, undisciplined and inadequately skilled Serbian national militia’s soldier from Serbian - Ottoman wars (1876 - 1878) to a disciplined, stubborn and very skilled warrior in the wars Serbia fought between 1912 and 1918. Thanks to universal conscription service, until the first decade of 20th century Serbian soldier become very valuable tool in the hands of carefully selected and highly educated and trained officers, for implementation of national goals. Although the regular compulsory military service period was two years long most of the Serbian conscripts spent in the barracks only five or eight months. During this shorter period of service, Serbian soldier went to training up to the battalion’s level. Becoming the reservists, Serbian soldiers were regularly called up every year for up to 30 days of additional military training. This kind of training was performed on the regimental and combined exercise level. That was the way to train most of the conscripts adequately without keeping them for a long time in the barracks. In 1893, after the whole first “call up” soldiers (i.e. those in the ages between 21 and 31) went through the basic military training, Serbian General Staff started to implement regularly large scale combined maneuvers on the division and corps level. The achievements of the process were very impressive. With the population of 2.922.058 inhabitants in 1910, on the basis of standing force consisting of 2.349 officers and 29.206 NCO’s and common soldiers, Serbia was able to mobilize war army comprised 10 infantry and one cavalry divisions with 286.818 men within field army, 55.580 men of territorial army organized in 60 3rd “call up” battalions and 3.310 men of so called “Final defense”. Until the first Balkan war broke up in 1912, three “call up’s” included soldiers born between 1867 and 1891, that all went through short time compulsory military service within standing army. Thanks to carefully carried out compulsory military service and positive selection of commanding officers and NCO’s, Serbian army performed successfully during the wars waged between 1912 and 1918.