This thesis studies the influence of ethnicity, nationality, and occupation upon military selection of the residents of Ohio during the First World War. This is a quantitative study, based on a data set constructed from samples of the 1910 and 1920 censuses and The Official Roster of Ohio Soldiers, Sailors, and Marines in the World War, 1917-1918. Chapter I introduces the sources and the methodology. Chapter II examines the ethnicity of conscripts, and whether or not ethnic identities affected draft registration or military selection. Chapter III examines the numerical significance of resident aliens in the military population. Chapter IV examines the influence of social class on conscription: determining whether persons of wealth avoided military service and the influence of occupational deferments on the population at risk. Chapter V concludes the thesis by summarizing the results.