One of the most fundamental measurements in cosmic rays is the determination of the rigidity dependent fluxes, or spectra, of primary nuclei in cosmic rays, such as H, He, C, and O. These primary nuclei are believed to be produced and accelerated by supernova. The spectra carry information about the acceleration and propagation of cosmic rays. Another class of nuclei is produced by nuclear interactions of these primary nuclei with interstellar matter, such as Li, Be, and B. The spectra and relative abundances of these nuclei reveal propagation parameters, such as the average amount of interstellar material traversed by cosmic rays and their age. This thesis discusses a measurement of the carbon and oxygen fluxes, as well as their ratio, in cosmic rays with rigidity from 2 GV to 2.6 TV, based on data collected by AMS during the first 5 years of operation onboard the International Space Station.